ガラスのアスプ

After Glass Asp’s triggered ability resolves, the affected player has the ability to perform a special action of paying {2}. This action may be performed any time the player has priority, and it doesn’t use the stack. It may be performed only once. Once that player’s next draw step begins, the player no longer has the ability to perform this action. If the player performed the action, the delayed “lose 2 life” triggered ability won’t trigger. Otherwise, it will.