This intriguing cleric-only magic item has many options open to it. At first glance, it looks the like reverse of the rule card Negative Planar Energy (73/NS), draining an opposing undead champion just like the undead would drain others.

However, this item is much nastier than it looks. The key part is that you can drain levels from ANY undead in play, so it can target undead hiding in the pool (Gatekeeper (422/3rd) is a particularly tasty looking target for this power) of your opponent, or even an undead champion belonging to a player not involved in the combat. To work, the item has to get into battle. Some champions are particularly nice to be combined with this card, including Klik-Ka'cha (77/AR), Halcyon (16/1st-chase), Verminaard the Dragonmaster (42/DR), Nemon Hotep (67/NS), Tyvorg the Frost Giant (45/DU), or any clerical avatar.

It should also be noted that if not used right away, it can be used to get rid of an undead during battle, including an opposing ally before it takes effect. OR you can wait until you use another draining power, like the Amulet of Undead Aura (9/NS-chase) or Sword of the High King (5/PO), then activate the Holy Symbol (which you can do because it's already in play) to finish the undead destruction.

I would suggest using this in any combat deck that uses many clerics (granted, that's not a lot of decks, but I know there are a few out there...).