Pizza Steve is a character from Uncle Grandpa, the Cartoon Network series that ran from 2013 to 2017, where he is an anthropomorphic pizza slice who acts far cooler than he really is. Clips of his voice are shared online because his bragging tone makes even simple lines sound funny. This leaf on your nose moment is used as a short reaction and distraction gag in edits, especially where a character is focused on something minor while bigger events happen around them.