Grez The Lizard Lord was a neutral monster in League of Legends described in game as "A melee monster with large amounts of health. Killing this foe grants a slowing attack that deals damage over time.". It used to spawn on Twisted Treeline, in the center of the map with no other monsters around it.
When killed, Grez granted his killer the Blessing of the Lizard Elder buff, where every hit deals 10-44 (10 at level 1, increasing by 2 damage for every level gained) bonus true damage twice and slows enemies (8/16/24% for melee or 5/10/15% for ranged attacks) for 3 seconds.