At

the

beginning

of

each

player's

upkeep,

that

player

gains

control

of

this

enchantment.

When

you

gain

control

of

this

enchantment

from

another

player,

choose

a

creature

you

control

and

an

opponent.

Flip

a

coin.

If

you

lose

the

flip,

that

opponent

gains

control

of

that

creature.