Trochomancy

Trochomancy: Remove 13 cards in the target Methuselah's ash heap from the game to get +1 bleed. Not usable if there aren't enough cards in that ash heap. You cannot play another action modifier to increase this bleed.

My question is: does the target Methuselah get to choose which cards are removed? Or does the acting Methuselah?

Acting Methuselah.