Ruthy, Lady of Cuteness

+1: Summon 1 1/1 green cat token with menace and give one creature +1/+1 until the end of the turn
-3: Summon X 1/1 green cat tokens with menace where X is the number of extra mana spent
-7: Give all creatures you control one +3/+2 counter and give them trample and menace until the end of the turn