Interesting idea! While I'll admit I'm not too interested in the ability to generate skeletons, it's a nice approach to PC. It's almost a PC lobo-effect, or more closely a PC Liquid Shadow. It would certainly increase the appearance of Skeletons, too, but I'm still not convinced you could make a strong deck intentionally generating skellie-swarms.
One question, what would happen if you used this on a weapon and then Flying Weapon? I imagine it would keep it's Skeleton generation ability, but it's your card.