Swarm of Centipedes (PHNI-EN085) [Phantom Nightmare]

If this card is flipped face-up: You can target 1 other monster on the field; change it to face-up Attack Position or face-down Defense Position. You can only use this effect of "Swarm of Centipedes" once per turn. Once per turn, during your Main Phase: You can change this card to face-down Defense Position.