Hedgehog

A ter'angreal in the form of a carved wooden hedgehog no bigger than the last joint of a man's thumb.

References

TDR,Ch13 - The hedgehog and several other ter'angreal are stolen from the White Tower by Liandrin and her Black Ajah cronies.
TDR,Ch21 - Verin gives a list of the stolen ter'angreal to Egwene.
TDR,Ch25 - When a woman channels into the hedgehog they fall into a dreamless sleep for half a day.
TDR,Ch53 - The hedgehog is left as a trap for Moiraine, but instead it catches Faile sending her fully into Tel'aran'rhiod.
TDR,Ch55 - In the wolf dream, when Perrin breaks the chain holding the falcon, he finds himself back in the room with Faile. The hedgehog is broken in half.