The porn video tag "mr-krabs" refers to a character from the popular animated television series, SpongeBob SquarePants. Mr. Krabs is a crab and owns the Krusty Krab restaurant where he often interacts with other main characters like SpongeBob and Patrick Star.
In a porn context, "mr-krabs" could be interpreted as a roleplay or fantasy scene where one participant takes on the persona of Mr. Krabs from the show. This tag may attract fans of the series who enjoy incorporating elements of their favorite cartoons into their adult content viewing experience. Note that this tag is specifically related to the character and not the actual animated series itself