S06E13: We'll Have A Good Time Then...

Shawn and Jack's ne'er-do-well father Chet reappears on campus suddenly and, confronted by an angry Shawn, promises that he has come to stay and make amends to his sons for never being there for them. But after treating them to a steak dinner and consuming a piece of Rachel's "killer" chocolate cake, Chet suffers a heart attack.