The Cyclophages are one-eyed, four-legged, bipedal creatures that feed on cyclopes.[1]
Leela's last will specified that when she died, her body was to be fed to a Cyclophage. When the Planet Express crew crashed back to Earth after passing through a wormhole, Leela fell into a coma from which she could not be woken. Her body was later taken to a Cyclophage preserve, where a Cyclophage nearly devoured her: she woke up in time however and the crew narrowly escaped the creature.
Back on Earth, the crew was attacked at Planet Express headquarters by the same Cyclophage, which had clung to the ship and returned with them. The creature was killed when it swallowed Bender, whose newly-installed doomsday battery overloaded. However the other members of its species were safe at a zoo.