Mexican SpongeBob is an alternate-universe version of SpongeBob SquarePants, who is from a universe where SpongeBob is either Mexican or just wears Mexican clothes. He only appears in the comic Bikini Bottom 2.
He looks like SpongeBob, but wears a sombrero on his head and Mexican clothes.
He appears at the end in the crowd of alternate-universe characters. He is seen next to Mummy SpongeBob.