Gravity Warrior (PRC1-EN020) [2012 Premium Collection Tin]

1 Tuner + 1 or more non-Tuner monsters
<br>When this card is Synchro Summoned: It gains 300 ATK for each face-up monster your opponent controls. Once per turn, during your opponent's Battle Phase: You can target 1 Defense Position monster your opponent controls; change it to face-up Attack Position, also it must attack this turn, if able.