Meaning

1 senses
  1. (slang)A sarcastic assertion that something that has not been satisfactorily explained by science is therefore evidence of extraterrestrial life on Earth.

Origin

From alien + did + it, modelled after goddidit.

From alien + did + it, modelled after goddidit.

Wiktionary, CC BY-SA 4.0 · source

See also

neighbours in the dictionary
aliensdidit — meaning, examples, forms, synonyms | Krumeto