Ricky Höek is the son of Ren Höek and Stimpy Kadogan, who only appears at the end of the episode "Stimpy's Pregnant".
He is a fecal baby, birthed from Stimpy as John Kricfalusi's way of wanting to show parents that "Shit can be children too".
The character, much like the episode itself, was universally disliked by parents, and later, the internet, who see him as a complete nightmare, for the fact that he's a living, breathing, baby made entirely out of feces.