Water and the Brain is the first part of the thirteenth episode of Arthur Season 2. Water and the Brain aired on February 7, 1998. It aired with the episode "Arthur the Unfunny".
Muffy is throwing a party at a water park and everyone is invited but Brain refuses to go. Arthur and Binky discover that the Brain is afraid of water and try to help him get over this fear so he can go to Muffy's party.