Aliens are of yet unconfirmed species that may or may not exist outside of Earth.
Aliens have not appeared officially and are mostly regarded as fiction. Those who believed in aliens are seen as delusional or mentally unstable. Aliens are generally believed to be small grey men with big black eyes.
A leprechaun known as Wayne Whittaker posed as a UFO-specialist after being summoned to Earth. His kin, the fairies, began kidnapping all first-born sons in an incident that was believed to be the result of ailen abductions. The abductions also led to a gathering of UFO watchers, one of them being Sparrow Jennings.
- Season 2
- Season 6
- Clap Your Hands If You Believe (mentioned only)
- Season 8
- A Little Slice of Kevin (mentioned only)
- Season 10
- About a Boy (mentioned only)
- Season 11
- The Chitters (mentioned only)
- Bobby Singer's Guide to Hunting (non-canon, mentioned only)