Omega bomb

The omega bomb was a weapon of mass destruction and a single warhead was capable of destroying an entire planet.

Fiction

The Transformers cartoon

The Quintessons, as part of their manipulation of the warring worlds of Xetaxxis and Lanarq, contacted the leaders of both worlds secretly as well as separately in order to sell the omega bombs that would have resulted in the mutual annihilation of both planets. After their plot was discovered, the Quintessons activated the devices in order to destroy both planets anyway but Rodimus Prime, Ultra Magnus and Sky Lynx destroyed the Quintesson cruiser before it could accomplish its dastardly deed. The Quintesson Journal

Animated cartoon

Blitzwing and Lugnut had spent the past few cycles blowing each other to smithereens with weapons Swindle provided them. But things finally came to a head when Swindle sold Lugnut the devastating omega bomb, a floating arsenal so massive, it actually carried him! Lugnut confronted Icy Blitzwing just outside of New Kaon's orbit, strapped to his new weapon of mass destruction. But Icy Blitzwing simply grinned (creepily) and revealed an even more massive omega bomb. Both Decepticons opened fire, and wound up nuking New Kaon in the process. It was around that time they realized Swindle played them both for suckers. Everything Must Go