My PCs recently derailed a whole bunch of my planning through creative play – which is fine, the surprises make the game more entertaining for me this way – they ended up in the Slumbering Ursine Dunes and here are converted monsters for my own reference with abbreviated 5e stat blocks.
Part rare floon, part ocular bat, part huduk, the Grue is all fearsome. Lurking in its aura of perpetual darkness few have actually seen the creature—and even fewer have lived to tell of it. What is known is that it strikes with a large maw of razor-sharp teeth and that it has the look of a perverted small woodland beast blown up and distorted into demonic form.
Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 7 (2d6) piercing damage.