Mayosenju Daibak (SP17-EN003)

Pendulum Effect : When a "Yosenju" monster you control declares an attack: You can have that attacking monster gain 300 ATK until the end of the Battle Phase.
Monster Effect : Cannot be Special Summoned, except by Pendulum Summon. This card's Pendulum Summon cannot be negated. If this card is Normal or Special Summoned: You can target up to 2 cards on the field; return them to the hand. Once per turn, during the End Phase, if this card was Special Summoned this turn: Return it to the hand.