Greedy for Tweety is a 1957 Warner Bros. Looney Tunes cartoon directed by Friz Freleng.
The mouse hits Sylvester's bandaged leg, then Hector's, causing both of them to hop and scream in pain.
When Granny leaves, Sylvester uses his newly built device to put a stick of dynamite in Hector's cast.
Hector, horrified, quickly grabs a crutch and rows himself with the bed and switches casts with Sylvester.
Hector's cast explodes on Sylvester's leg, causing him to shriek in pain, at which point Granny comes in and informs the trio that there was nothing wrong with them and they are therefore being dismissed.