If this hits the field, just scoop. It's one of the best 5-drop tribal creatures in the game (Brood Sliver and Horde of Notions being two others). If you've built your deck correctly, you've got this guy out on turn 3 and then your opponent cries because he's lost the game. The search is awesome, since it'll get your best Slivers out when you need them (Magma Sliver, Pulmonic Sliver, Root Sliver, Shifting Sliver, or Sliver Legion come to mind). The stealing effect doesn't see much use since Crystalline Sliver will usually be on the field, however it can be fun if a Hivestone is on the field. It does cost one of each colour, but every Sliver deck runs at least a couple Gemhide Slivers in them, so it usually doesn't matter.
Pros: Sliver search, Sliver steal, 7/7 for 5 Cons: Costs one of each colour Rating: 5/5