Death crystal was a type of greenish crystal that could be present in a spherical shape. They could be used as ammunition and after being launched from a rifle weapon the crystal sphere would scatter into shrapnel pieces that could destroy entire starships even if they were made of the strongest metal known.
Generation One animated continuity
Blast Off learns of a weapon that made use of this ammunition and employed it on an Earth Defense Command ship. He and Runamuck would also attempt to destroy the Autobots that tried to discover the new Decepticon weapon.
Marvel Comics continuity
Devil's Due G.I. Joe vs the Transformers comics continuity