Matryoshka Doll

The Matryoshka Doll is a new available weapon in the upcoming zombie map Ascension. It replaces your Secondary Grenade slot, and you get equipped with three of them. When thrown, they act as a cluster bomb, exploding 5 times.

Trivia

 * Matryoshka doll is another name for a Russian nesting doll.
 * They are also known as Babushka Dolls.