Temporary Insanity is the first short from Episode 6 of Animaniacs.
Plot[]
Mr. Plotz's secretary gets sick and leaves him with a phone number to dial a temp-secretary, but because of his lack of knowledge on how telephones work he accidentally dials the Warners, having them come over and "help" Mr. Plotz out. In the end they destroy the building over a dispute on who answers the phone, the call itself being the secretary letting Mr. Plotz know that she'll be sick for another day, causing Mr. Plotz to rely on Yakko, Wakko, and Dot to be his secretaries for another day.