Can only be attached to a wizard. The attached champion becomes undead and gains 5 levels to his base level. This item remains attached to him until he's discarded; it cannot be discarded in any other way.
Copyrights:
TSR
Wizards of the Coast
This +5 magical item is only effective with champions designated as wizards. All other champions, even those capable of casting wizard spells, cannot use this card at all. The +5 granted by the Arcane Formula for a Lich is added directly to the champion's base level, and that champion is now considered undead. Once attached, this magical item cannot be removed by any means except through causing the champion to be discarded. Not only does this mean that it is not affected by cards like Crystalbrittle (53/RR), but it also cannot be borrowed by Drawmij (276/4th) and the like.
Since this magical item will have a limited number of potential champions in a deck with many champion types, it's recommended that you have several wizards in a deck with this item. Combining it with other magical items, like the Amulet of Undead Aura (9/NS-chase) can make for a deadly combination. Especially if they are attached to a high level wizard like Kanchelsis (483/4th).
Many high-level mages have tried to perform the ritual that will lead to lichdom, but few have any real success. The process is long and expensive, and if done incorrectly, usually results in irreversible death. Some wizards, however, still feel this is a chance they're willing to take to continue their quest for power and knowledge.