Alec Holland is an individual known by John Constantine.
Holland resided in "The Bloody Swamp" according to John Constantine. People would often try to contact Holland, but would get through to Constantine instead.
- In the comics, Alec Holland was known as the Swamp Thing: a mutated humanoid plant creature who tasks himself with protecting The Green, an elemental force which connects all plant life on planet earth. He was often aided by John Constantine in the various occult circumstances they would come across.
- Holland's only appearance in the Arrowverse is a 2014 promotion for the NBC show Constantine . The "phone number" of John Constantine was given out, and when called, the answer message from John stating "Hello, you've reached John Constantine. And that's John Constantine. If you're looking for Alec Holland, try the bloody swamp." A reference to Holland, and his role as the Swamp Thing.