Wondrous item, unique
This small metallic object is comprised of rune-covered parts made from different metals, linked together with a variety of gears, bands, bits, and bobs. The metals are all different colors, making the grenade shine with a rainbow of color when held up in the light.
As a bonus action, a creature can turn a special key to arm the grenade. Once armed, the grenade explodes in a matter of seconds. As an action, the wielder can hurl the grenade up to 120 feet. At the end of their turn, the grenade explodes. All creatures within 60 feet of the grenade when it explodes suffer the following effects:
The grenade explodes immediately if a creature places it in an extradimensional space or teleports while in possession of it. The effects of the explosion will be felt at both the origin and terminus of the teleportation, but only affecting all creatures within 30 feet of either location.