Squid the Horse is an alter-ego of Squidward Tentacles who appears in the episode "Pat the Horse."
He looks just like Squidward, but behaves more like a horse. He still retains several characteristics of Squidward, however.
Role in episode
After Pat the Horse runs away from Mr. Krabs, the latter uses Squidward as the replacement horse. Squid the Horse is also used to race against Pat the Horse.