Huh. The interesting thing about this card is that if this is enchanted to a Hill Giant, it doesn't matter if it is blocked by a Giant Spider or a Giant Cockroach, it will kill both of them. With the spider, you'll just have to wait until the trigger is done resolving.

Assuming that people understand that, this is kinda good. Might be better as a creature, however. I'd be hesitant to enchant my creature with anything that requires my opponent to do something for it to function.

By "requires opponent to do something," you mean blocking the creature?