Looney Tunes - Feed The Kitty (1952) (the video)
From Wikipedia article:
A segment of Feed the Kitty, in which Marc Antony believes that Pussyfoot has been turned into a cookie (and unaware that the kitten is actually perfectly safe), was the subject of an homage in the Pixar film Monsters, Inc. In it, monster James P. Sullivan (“Sulley”) believes that a little human girl he is protecting has fallen into a trash compactor and reacts nearly shot for shot as Marc Antony did in his cartoon short.
Oh man… One of my favourite episodes from Looney Tunes/Merrie Melodies.
Reblogging this directly from original post because I don’t understand why some people reblogged it but removed the description/caption.