The Sludge

The Sludge was a strange, destructive jelly-like creature which first menaced the world in the pages of IPC's Lion comic, until it was apparently destroyed by Canadian newspapermen Bill Hanley and Rick Slade using Formic acid. Nevertheless, a fragment of the Sludge survived and returned to take on the intrepid pair again in the appropriately titled 'Return of the Sludge', this time falling prey to a shoal of Portugese Man'O War jellyfish. Nothing if not resilient, the Sludge also cropped up again later to oppose Robot Archie in his own strip.