Let’s come up with a monster.

Maybe just add werewolves as meat shields: they could transform into wolves, bears, tigers, spiders, and other creatures at will. Each transformation would have its own stats, advantages, and disadvantages. Wolves are fast, bears are tough (sometimes very useful – to absorb a hit), tigers attack incredibly well...
I think this idea could be developed further if you like it, but the level should be no more than 4. Go for it!