It is a long and light pink novelty toy tongue. There's a tag on it that reads "Novelty Toy." The word "novelty" is imprinted in dark purple, and the word "toy" is imprinted in light orange, with a ™ next to it.
Role in episode
Sandy grabs it and plans on pouring hot sauce on it, thinking it is SpongeBob's real tongue. After SpongeBob surrenders and Sandy drinks the hot sauce, SpongeBob reveals it is a Novelty Toy Tongue and uses it to trap Sandy and spin her and attempts to karate chop her before she does so to him.