Fe, The Fairy

Haste, Flying, Double Strike
Unleash (You may have this creature enter the battlefield with a +1/+1 counter on it. It can't block
as long as it has a +1/+1 counter on it.)
{3}{b}{b}{b} Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it
becomes monstrous.)
When this card becomes monstrous, this creature fights any number of other creatures.