Zrik is a zombie involved in the Walk Like a Zombie promotion and Dimension of the Damned.
Walk Like a Zombie
Talking to him for the first time of every prestige will complete the corresponding task (to find and talk to Zrik), as well as awarding the player 2 additional brain stickers and a medium XP lamp.
Zrik's location changes at the start of each hour, and does not appear to be synchronised across all worlds.
He has been found in the following locations:
Dimension of the Damned
Zrik features in Dimension of the Damned, where he sells items for players to purchase in the mode's starting location in Falador.