"It!" is a horror short story by American writer Theodore Sturgeon, first published in Unknown of August 1940. The story deals with a plant monster that is ultimately revealed to have formed around a human skeleton, specifically that of Roger Kirk, in a swamp. P. Schuyler Miller described "It!" as "probably the most unforgettable story ever published in Unknown. "
Plant-based swamp monster similar to that in the story appear in various comic books. Among these characters are Hillman Comics' Heap in Airboy Comics, who debuted in what was intended as a one-time appearance in the feature "Skywolf" in Air Fighters #3 (December 1942).
Early depictions of the Heap look highly similar to the Looney Tunes/Merrie Melodies character Gossamer, an orange-furred, practically featureless monster in sneakers who menaced Bugs Bunny in the 1946 animated short "Hair-Raising Hare" before going on to other appearances (named "Rudolph" in one).
Solomon Grundy in All-American Comics is the result of a criminal having fallen in a swamp, though he did not have a plantlike appearance.
Sturgeon's story continued to show influence after the relaxation of the Comics Code Authority's restrictions on horror late in 1971. Man-Thing first appeared (in an unrestricted black and white magazine-size comic) from Marvel Comics in May 1971, and DC Comics introduced Swamp Thing in the anthology comic House of Secrets #92 in June 1971. A different character, based upon the House of Secrets story, also called Swamp Thing debuted in issue #1 of its own title (November 1971).