The Ghostfence

This spell costs {1} or {p/w} less to cast for each Elf
and Cleric in your graveyard.
At the beginning of each end step, create a White
2/2 Spirit Creature token with Flying.
Spirits you control have +0/+4, Defender
and are Walls in addition to their other types.
You and lands you control have Hexproof as long
as you control at least one Spirit.