At the beginning of your upkeep, put two trigger counters on Trapped Chest. You may then pay

where X is equal to the number of trigger counters on Trapped Chest. If you do not, sacrifice Trapped Chest, it deals X damage to you and you draw X cards.

: Target player gains control of Trapped Chest.
For Challenge # 135. That's more words than I was expecting. That, and I'm not sure if this really does the idea of a 'trapped chest' justice. Seems more like an evil jack-in-the-box. That, and it requires people to understand timing, and putting things on the stack. Humpf.