Kai, True Pollyanna

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)

When this creature enters, each player chooses one-
•That Player gains 3 life
•That Player draw one card then discard a card

{3}{w}{g}: Exile Kai, True Pollyanna from the battlefield, return it to the battlefield transformed. Activate this only if every player gained life this turn