Lizard Rick is a lizard person-version of Rick seen climbing walls at The Citadel.
He first appeared in the Season 3 premiere episode, "The Rickshank Rickdemption", and can be spotted crawling on the walls of the Citadel. It is unknown what happened to him following the fall of the Galactic Federation and near destruction of The Citadel.
He most likely has affiliations with lizard morty.
Lizard Rick is a purchasable avatar in the game Pocket Mortys.