You summon Puck as a companion. It appears in an unoccupied space that you can see within range. He disappears when it drops to 0 hit points or when the spell ends.
Puck is friendly to you and your companions for the duration. Roll initiative for the creature, which has its own turns. It obeys any verbal commands that you issue to it (no action required by you), as long as they don't violate its alignment. If you don't issue any commands to the fey creature, it defends itself from hostile creatures but otherwise takes no actions.
Once Puck is summoned, he cannot be on the Material Plane beyond the next sunrise. Likewise, once he is dismissed, he cannot be summoned again until the next sunrise.
The GM has the fey creature's statistics.