Noh Mask

The Noh Mask was an evil mask carved from a tree with a shard of the Shikon no Tama in it.

History
It was sealed by Kagome's great-great-great-grandfather who exorsiced it many years ago and placed in a box where it remained until Kagome brought a shard of the Shikon Jewel with her to the present. The seal on the box was then broken and it attacked Grandpa and tried to devour him but he somehow managed to survive.

Trivia
A conundrum is made by this mask, since the jewel shard in the mask was collected in the present and not the past, it stands to reason that the shard still exists in the past uncollected. This was brought up at a convention where Rumiko Takahashi was a guest speaker, who merely stated it was an error in logic and should just be overlooked.