Entrancing Melody

Sorcery

Gain control of target creature with mana value X.

2017-09-29:
If a permanent has {X} in its mana cost, X is considered to be 0.
2017-09-29:
The control-change effect of Entrancing Melody lasts indefinitely. It doesn’t wear off during the cleanup step.
2017-09-29:
In a multiplayer game, if a player leaves the game, all cards that player owns leave as well, and any effects that give the player control of permanents immediately end.