Exploding Sphere

The is a ninja tool stored in Tenten's large scroll. It's a metal sphere with kunai welded into it, which also has a hidden explosive tag that causes it to explode upon contact, sending out kunai and fragments of the sphere as shrapnel.

Trivia

 * This tool's name was established in Naruto Shippūden: Ultimate Ninja 4 and Naruto Shippūden: Ultimate Ninja Storm 2, as it was unnamed in both anime and manga.
 * In the anime, an unidentified Kumo-nin, who was reincarnated by Kabuto, used similar bombs (though they were spikier and had no explosive tag on the outside).