You gain life equal to the damage dealt, but not more life than the player's life total before the damage was dealt, the planeswalker's loyalty before the damage was dealt, or the creature's toughness
That holds true for Kyogre V from Crown Zenith
Cards that were produced in limited numbers, such as tournament prizes or special promotional releases, tend to be much more valuable due to the difficulty of obtaining them
This is an incredible sweeper since it demolishes all artifacts, creatures, and lands
Granted this card only gives a -1/-1 until the end of turn but it does so at instant speed, for a single mana, and bolsters your creatures, Planeswalkers, or get's you closer to having someone corrupted
If you're not doing something illegal or damaging the booster pack in any way, I don't see any problem with taking advantage of an obvious flaw in the system and stacking the odds in your favor