Ko Sharmus' large bomb

Ko Sharmus' large bomb was a large spherical explosive kept by Ko Sharmus on the Planet of the Boundary.

History
With Cyber-Warrior execution units approaching, Ko Sharmus led Ryan Sinclair and Ethan to his very limited weaponstore, where Ryan was dismayed by the idea of fighting the Cybermen. Ko Sharmus and Ethan convinced him of the necessity of the action and Ko Sharmus handed Ryan the bomb, ordering him to survive and be a pacifist again when they had won.

Later, after the Cybermen destroyed Ko Sharmus' sentry guns, he ordered Ryan to prepare the bomb. Ryan was nervous due to his lack of coordination with many things, but on command, Ryan tossed the activated bomb into the middle of the execution units like a basketball. The bomb destroyed all of the Cybermen and Ryan celebrated his victory only to have more Cybermen arrive. (TV: The Timeless Children)