Iceworm 2014
CR 1 monstrosity
Small monstrosity, unaligned
Can breathe air and water.
Can’t abide constant warmth. Each hr it spends in an area with temperature above 40 degrees Fahrenheit worm must make DC 15 Con save or suffer one level of exhaustion that can’t be removed until it finishes a long rest in area with temperature below 40 degrees.
Has disadvantage on attack rolls when within 5 ft. of a strong source of heat that isn’t a warm-blooded creature’s natural warmth such as a torch or campfire. In addition the iceworm can pinpoint the location of warm-blooded creatures within 90' of it and can sense the general direction of such creatures within 1 mile of it.
Has advantage on saves and ability checks made to escape a grapple.
Source: Tome of Beasts 3 (Kobold Press) · License: OPEN GAME LICENSE Version 1.0a details