0: roll a six-sided die.
1 or 2 — +2, then create two 1/1 green squirrel creature tokens. they gain haste until end of turn.
3 — -1, then return a card with mana value 2 or less from your graveyard to your hand.
4 or 5 — comet, stellar pup deals damage equal to the number of loyalty counters on him to a creature or player, then -2.
6 — +1, and you may activate comet, stellar pup's loyalty ability two more times this turn.