Polukranos, Squirrel Eater

{x}{x}{g}: Monstrosity X. (If this creature isn't monstrous, put X +1/+1 counters on it and it becomes monstrous.)
When Polukranos, Squirrel Eater becomes monstrous, it deals X damage divided as you choose among any number of target Squirrel creatures your opponents control. Each of those creatures deals damage equal to its power to Polukranos.