He is a pale yellow sea sponge with olive green holes and white hair. He wears a pine green shirt, a white undershirt, transparent light blue glasses, brown socks, and dark blue slippers. He also holds a black walking cane and a walker. Being an elder, his skin is rather wrinkled, and he appears to only have one tooth, which is on the right side of his mouth.
He is first mentioned in "Rock Bottom," where his likeness is exhibited through SpongeBob. In his next appearance, he is depicted in SpongeBob's mind in "The Sponge Who Could Fly." He is known for his wise sayings, which include "If we were meant to fly, we'd have propellers on our heads or jet engines on our backs" ("The Sponge Who Could Fly") and "Don’t run for a bus, especially one that's going up at a 90 degree angle" ("Rock Bottom").
He once said, "Don’t run for a bus, especially one that's going up at a 90 degree angle." and SpongeBob realized he was right when he tried running for a bus going up a 90 degree angle and "If we were meant to fly, we had have propellers on our heads or jet engines on our backs." which SpongeBob remembered when he was trying to fly.
Late in his life, he had a cane then eventually a walker.