This monster is a one-of-a-kind. There may be more reptile bears, but they should be faster, non-blind and have sharper claws (1d6 of damage, perhaps). This specific individual monster will appear in a dungeon adventure in a later post.
The reptile bear is 17' high when standing on its hind legs and is completely covered in scales. It's strong and has sharp teeth, but is old and somewhat decrepid; its claws are dull. Its saliva has a slight stunning effect. Anyone bitten must save vs poison or suffer -2 on all actions for 1d6 turns. This effect stacks with each bite. It doesn't want to fight, however, and will only try to make room for itself to lumber out through the exit of whatever room it's in.