Convex Knight

“If a Machine monster is on the field and this card is in your hand: You can Special Summon this card in Defense Position, then you can make this card's Level become the Level/Rank of 1 Machine monster on the field. During your Main Phase: You can send 1 EARTH Machine monster from your Deck to the GY, then until the end of this turn, this card gains ATK equal to the Level of the monster sent to the GY x 100. You can only use each effect of "Convex Knight" once per turn.”