You can only use the (1) effect of this card’s name once per turn.
(1) If the turn player Summons exactly 1 monster: Destroy that monster, and if you do, Special Summon 1 “Mask Token” (Spellcaster/DARK/Level 1/ATK ?/DEF ?) to the destroyed monster’s controller’s the field. Its ATK/DEF become the ATK/DEF the destroyed monster had on the field, but it cannot attack directly.
(2) If this face-up card leaves the field, destroy all “Mask Tokens” on the field.