Squidward Tennisballs was a name Squidward Tentacles was called on the episode "The Great Snail Race" by the mailman
where delivery man call squidward tentacle SquidwardTennisballs
Delivery Man: Package, sir.
Squidward: A-ha! (Squidward signs a clipboard) I can’t believe it’s finally here! (delivery man hands him the cage)
Delivery Man: Here ya go!
Squidward: Oh, thank you, thank you, thank you. (hands him the clipboard)
Delivery Man: Thank you, Mr...Tennis Balls.
Squidward: That’s Tentacles! (slams the door shut)
SpongeBob: Squidward’s last name is Tentacles?
Patrick: Poor guy.