Trick or Treat!

At the beginning of each player's upkeep, the
player in the direction to the left of the turn
player gains control of all creatures controlled by
the turn player.
Whenever a player gains control of a creature,
that player may choose to pay 5 life. If they do,
that player puts a +1/+1 counter on each creature
they gained control of that turn. Otherwise, they
draw a card and sacrifice two creatures.