Prosperous Thief (-346) - Foundations Jumpstart

Ninjutsu 1U (1U, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)

Whenever one or more Ninja or Rogue creatures you control deal combat damage to a player, create a Treasure token. (It's an artifact with "T, Sacrifice this artifact: Add one mana of any color.")