My current main D&D campaign has a theme of nature and magic running amok, so I’m always on the lookout for twisted versions of natural creatures. The flame bear is an example of such a critter, along the same lines as the somewhat iconic winter wolf (which I’ve already used): smarter, bigger, elementally-infused version of a famliar animal.

Note that I’m not too worried about my players seeing these stats, as most of the monsters I use are commonly available. Also, my players tend to prefer fewer battles with more interesting foes, so I’m working on a legendary version to throw at them.