Trample
If Blastproof Juggernaut is in your hand during your upkeep, reveal it and lose 1 life.
“It is a great evil to look upon mankind with too clear vision. You seem to be living among wild beasts, and you become a wild beast yourself.”
—William Beckford, Episodes of Vathek
For Challenge # 142. Both Alpha and Arabian Nights seemed willing to accept that players were generally honest, between Jandor's Ring and Sindbad. Granted, both of those cards deal with cards that were just drawn. It's about as hard to cheat with Sindbad as it is to stack the deck.
Still, I figured it would be interesting if we extrapolated from there and said that Wizards trusted the players enough to report when they injured themselves, even if it became incredibly easy to fudge. Maybe that's not reasonable in a world with ante, but que sera.
Also, I originally didn't have the card reveal itself. But I figured it would be really wierd to have a player just start dying at a table with no explanation. Though, that's kind of cool, too...