Brehua, Kitsune Ascended

As this creature enters, it becomes summer. (Whenever a creature enters the battlefield, its controller gains 1 life.)
As long as it is summer, whenever a creature
enters the battlefield under an opponent's
control, that creature deals damage equal to
its power to its controller.

{2}{r}: Put a creature from you hand onto the
battlefield. Each opponent creates a token
copy. Each player sacrifices these creatures
at the beginning of the next endstep.