Dr. Swampo
The Mastermind of the Bog, or Dr. Swampo is a Gotham City urban legend (or is it?) about a creature that appears to be made from vegetation piled into a vaguely humanoid shape. It is said to kidnap unsuspecting visitors to Slaughter Swamp and drag them back to his secret laboratory. Sometimes the victims are released, sometimes they are never heard from again.
Since the creature has never been photographed (apart from a single, grainy distant shot that many say is of a ground hog on its back legs, but nevertheless was run in The Bugle), and since most of the recent surviving witnesses are hobos, no one in town seriously believes in Dr. Swampo. The sole exception might be Hans Gruberman who has speculated that Swampo might be an Atlantean “Vorgath”, a type of biological Android, thinking machine.
The laboratory of the fiend is said to be underneath the surface of the Swamp in a series of caverns and artificial metallic rooms. It of course has never been located or seen by reliable witnesses.