|What makes you think I can do that?|
This page contains conjecture or inductive logic about a subject that is not explicitly mentioned or explained in the canon.
A list of Supernatural inconsistencies that have occurred during its run.
- When an angel was killed, burnt wings would be appear on the ground next to the body. Beginning in Season 9, this effect was no longer used as all of the angels wings burnt off during the fall. However, in Meta Fiction many dead angels can be still be seen with their burnt broken wings. This affect wasn't seen again until Season 12 in Lily Sunder Has Some Regrets.
- The arrival of angels in 2009 sparked concern for the demons as angels had not officially been on Earth for maybe thousands of years. Anna Milton stated that her own garrison was forced to watch humans and not interact with them. Castiel stated to Dean that angels did not walk among humans for 2,000 years prior to Dean's resurrection. However, in Lily Sunder Has Some Regrets, it is revealed there was an angel garrison permitted to be on Earth only about 100 years ago and Castiel was a member of this garrison before joining Anna's. This was cleared up after Castiel mentioned the special circumstances surrounding the situation, calling it an "anomaly". Nevertheless, in Angel Heart Castiel mentions that the Grigori were stationed on Earth for centuries. The Nephilim Jane also existed on Earth for years without Heaven being aware.
- In Tombstone, Castiel is not able to resurrect a Security Guard, despite the fact that Seraphim can resurrect humans easily. The explanation can't be the loss of his wings, since Gadreel resurrected both Castiel and Charlie Bradbury, after the Fall. Castiel was also unable to resurrect Sam in Beat the Devil. While he could resurrect Jack in Byzantium, it was stated that he could only bring Jack back for a few moments and could not heal the illness that killed him. It took a ritual curing the illness to make the resurrection permanent.
- In Hell's Angel, Amara refers to Lucifer as the "first son", which is inconsistent with statements made by Michael and Lucifer throughout season 5, in which Michael is the first son and Lucifer is the second. It is unclear why Amara said this.
- In Free To Be You and Me, it was explained that after an Archangel leaves his vessel, the vessel becomes paralyzed or worse. This depends on the archangel's strength as Castiel said: "Michael is much more powerful. It'll be far worse for you" to Dean. However, in LOTUS, after Lucifer was exorcised from Jefferson Rooney, the president was alive and healthy though he was only possessed for a few days. However, this may be intentional on the archangels' part, as Michael would later tell Dean that he wouldn't be a "drooling mess" after he's finished using him. During the alternate Michael's possession of Dean, Sam worried that Dean might end up being burned out. When Michael left him, Dean was clearly weak but otherwise ended up being okay.
- In Devil's Bargain, a weakened Lucifer stated the angels couldn't kill him if they tried. However, a similarly weakened Gabriel is shown running from Michael's angels in Exodus. Although, Gabriel was in a far weaker state than Lucifer as Asmodeus took grace from Gabriel for years.
- In My Bloody Valentine, Castiel consumes hundreds of hamburgers and a tray of raw meat due to the influence of Famine. He tells Dean that the burgers make him "very happy" and his facial expressions imply that he finds they taste delicious. However, in First Born, Castiel complains that by becoming an angel again, he has lost the ability to taste food like a human, and a sandwich tastes like "molecules" to him. On a side note, if angels could not taste food like humans, then every drink and snack would taste like molecules, in other words, "disgusting", yet Gabriel and Balthazar are shown consuming human foods with no trouble in the taste.
- In Goodbye Stranger, Crowley says to Naomi "If you remember our time in Mesopotamia the way I do, you know I'm a lover, not a fighter." Which implies that they spent time together in ancient Mesopotamia. Based on information from a demon in Weekend at Bobby's, Rufus discovers Crowley to be "17th century Scottish tailor named Fergus MacLeod from Canisbay" and it was supposedly the ghost of his son who leads Bobby Singer and the Winchesters to locate his burial site and bones in Scotland. However that area of the Middle East was known as Mesopotamia by the west up until the 1920 Iraqi Revolt, at which point it became known as the Kingdom of Iraq. Robbie Thompson, the writer of the episode, explained that the line was either going to reference "Mesopotamia" or "Belize," and decided to go with Mesopotamia because he thought it "sounded funny," only later realizing the mistake.
- There are many inconsistencies along the series about how many angels have actually seen God. Anna Milton stated in Heaven and Hell that their were only four (presumably the Archangels). It was also implied Gadreel had seen him, as Metatron stated God stationed him with watching the Garden of Eden. Later it is revealed that Metatron also met him, and ultimately Don't Call Me Shurley implies that God was in a room full of angels when he choose Metatron to write his Word.
- In the Season 8 episode The Great Escapist, Sam recalls a visit to the Grand Canyon when he was four-years-old, however, Dean mentions in Season 2 episode Croatoan that they have never been to the Grand Canyon. Writer Ben Edlund admits this to be a mistake on his part.
- In Slumber Party, Charlie Bradbury goes to Heaven after being killed by the Wicked Witch of the West. However, it is revealed in Captives that Metatron's spell not only closed off Heaven to angels but also to souls as well. Charlie should have been stuck in the Veil like Kevin Tran was rather than going to Heaven.
- In Funeralia, Naomi reveals that the presence of angels is necessary to empower the Heaven, which contradicts Season 9. After the Fall, only Metatron was left in Heaven, and although he still had his wings, he was just a regular angel and yet Heaven didn't collapse. However, during Season 9 more angels were alive in general and its only after the deaths of so many angels that Heaven falls into trouble.
- Lilith's plan for Season 3 and most of Season 4 seems to contradict her end plan to free Lucifer. For the entirety of Season 3 and most of Season 4, Lilith's plan was to kill Sam Winchester in order to rid herself of any opposition so she could claim the throne of Hell. She sent a number demons after Sam and personally attempts to kill him in the Season 3 finale, only to become scared when Sam proves immune to her powers. By the Season 4 episode The Monster at the End of This Book Lilith wants to make a deal with Sam and obtain his soul in exchange for escaping her fate as the final seal to Lucifer's Cage. Again, she makes an attempt to kill Sam, indicating she was pretending to offer a deal. By the Season 4's finale, she has submitted to her fate and lets Sam kill her as he was pre-destined to. This behavior is odd since Lilith had, pre-Season 3, ordered Ruby to act as a double agent and feed Sam demon blood so he would become powerful enough to kill Lilith anyway. Her motive for killing Sam appears inconsistent with her endgame. Killing Sam would prevent Sam from fulfilling his role as Lucifer's vessel. Even worse, once Lilith took control over Hell, all demons Sam encountered from then on sought out to kill him.
- In The Monster at the End of This Book its stated that Lilith had faltered after learning that she wouldn't survive, explaining her brief desire to stop her plan. At the end of Season 3, Sam is immune to not only her white light but her telekinesis as well which is something that is not seen again on the show. Its likely that Lilith was faking being scared to further manipulate Sam, especially since its unlikely that the Demon-Killing Knife could kill her.
- There seems to be an inconsistent statement regarding how Lucifer was cast into Hell and subsequently the Cage. It is initially said that God had been the one to banish Lucifer into his prison, though Season 5 reveals that Michael did it on God's orders following the conclusion of the First Heaven Civil War. Dean tells Rowena in O Brother, Where Art Thou? that God dumped Lucifer into the Cage himself, which is untrue.
- In Metamorphosis Dean and Sam first discover what a rugaru is from the hunter Travis. However, in Bad Boys a fourteen year old Dean, mentions his father is busy hunting a rugaru. Also in The Chitters, Sam comments to Dean that he was always afraid that Dean and John would be killed by a Rugaru.
- In the past all shapeshifter transformations (excluding the alpha) involved the shapeshifter's skin getting peeled/ripped off. However, in Blade Runners, a shifter is shown to seamlessly transform without shedding its skin. This ability was seen again in Bloodlines. VFX I/O Coordinator Adam Williams revealed he was puzzled at why this was. "No idea.. I kinda wondered the same myself. Originally I assumed there were "skinwalkers" and "shapeshifters" and the skinwalkers shed their skin - then I read the superwiki and realized the Alpha can transform without a skin shed but they are all the same monster. I guess sometimes legacy changes." 
- In The Chitters, Sam comments to Dean that he was always afraid that Dean and John would be killed by a vampire when they left him when they were kids. However, the Winchesters didn't know vampires existed until Dead Man's Blood in season 1.
- In The Scorpion and The Frog, Sam was able to recognize immediately the fossilized tooth as being that of a Gorgon. However in "Ouroboros" nor he or anyone else were able to recognize the creature that they were after before Rowena told them.
- Up until Season 11 finale Alpha and Omega, killing Amara has never been stated to cause any side effects. Prior to this, attempts have been made by Dean and the angels, though both have failed due to the power difference. It is mentioned that during the First War against the Darkness, God and the archangels did not destroy Amara simply because they were not powerful enough, and had to resort to tricking her and then imprisoning her. It appears that everyone simply was unaware of the effects that killing Amara would have as God had to explain it to them.
- After God is weakened by Amara, the sun and plants begin to show signs of decay revealing that God and Amara must both co-exist or cease to exist in order to allow Creation to remain. Rob Benedict, who portrays God, revealed that this change in script was due to the network which airs Supernatural the CW, an early script draft revealed God was originally intended to die at the end of the season until CW intervened.
- The first five seasons take place in the current time, matching with the year the season was aired in. Season 5 concludes around May 2010. Between Seasons 5 and 6, a year has gone by during which Dean has been living with Lisa and Ben Braeden, and by the time Sam gets his soul back in Season 6 episode Like A Virgin, a year and a half has gone by since the Season 5 finale. This would put the date around November 2011. However, the Supernatural crew decided to resume their tradition of giving each season the same year it was aired in, leading season 6 to be marked with the year 2010. Assistant Director Kevin Parks explains this decision: "They decided to do 'soap opera time', because they didn't want to have to push the year forward for the rest of the show's run. So, just like in soap operas when people's kids are toddlers and then suddenly teenagers, so too can Sam and Dean spend a year apart while no time has actually passed in reality." The timing went back to normal after this with season 8 being both aired and set in 2012-2013, as proven by Henry Winchester travelling to 2013 in an episode that aired in January of that year.
Death and Resurrection
- In Season 6 episode Appointment In Samarra, Death expressed his annoyance for the brothers' constant resurrections, as it disrupts the natural order, forcing him to clean up after them. However, in Season 11, Billie says that Death was amused by their resurrections.
- In Season 6, episode Mommy Dearest, Eve said that: "Each soul a beautiful little nuclear reactor. Put 'em together, you have the sun." However, Castiel said that each soul has the power of one hundred stars. However, this could be a general comparison on Eve’s part and Castiel could have been more literal.
- It was stated before in the series that only Nadia's Codex could break the code from the Book of the Damned, however in the episode Absence, Jack Kline was able to read the book and cast the spell "Necromancy" without the codex.
- In Season 12 episode Regarding Dean, Rowena MacLeod revealed to Dean to have met the Men of Letters years ago and ran away of their persecution. However in Season 10 episode Paint it Black, she was unaware of their existence until Olivette had told her.