What is a nightcrawler?

Nightcrawler (comics), a fictional superhero in the Marvel Comics shared universe.

Nightcrawler (film), a 1986 animated film based on the Marvel Comics character.

A type of worm, in particular the common earthworm Lumbricus terrestris.

Paralichthys dentatus, the Pacific halibut, a species of flatfish found in the Pacific Ocean.

Opistognathus macrognathus, a species of jawfish known as the yellowhead jawfish.

In professional wrestling:

- Nightcrawler (wrestler) (born 1982), Mexican professional wrestler.

- Nightcrawlers, the tag team of American professional wrestler Mike Quackenbush and Canadian professional wrestler Chris Hero.