Heaven-Tree Hydra

Trample

Whenever you cast a spell with {x} in its mana cost, generate {c} equal to whatever mana wasn't spent on {x}. The value of {x} must be at least 2 for this ability to trigger.

Whenever a creature spell with X it's mana cost
is cast or enters, Heaven-Tree Hydra gets a +1/+1 counter and a choice of reach or haste until end of turn.