The Sea Devil was a story from the TV Comic Annual 1979, in which the fourth Doctor and his companion Miss Young (clearly a thinly disguised Leela) combat mutant seaweed which is endangering an oil rig after being irradiated by a mysterious meteorite. Uncharacteristically, the Doctor makes no attempt whatsoever to determine if the mutant can be reasoned with, instead choosing to lure it into a mass of oil drums and set fire to them. Ah, well. We all have our off days...
This story does not feature the Sea Devils, strangely enough.