Castiel's dramatic entrance causes the lights to go haywire.
Electromagnetic Interference is an ability, or rather a result, a consequence/repercussion of a supernatural entity's presence.
Species with this ability
- Angels - Angels' true forms counteract electronics. When Angels first appear in vessels, or sometimes when they're near electronic ware, they can cause lights to flicker, spark, or explode.
- Demons
- Ghosts
- Pestilence - Pestilence's face on a security monitor was always masked by static.
- Famine - His presence caused lights to flicker, his anger them to explode.
- Reapers