Nemesis Shield

The Nemesis Shield is a powerful force field which renders a Transformer totally invulnerable to damage; even a direct blast from the chaos-bringer Unicron himself cannot penetrate it.

It is formed, along with the Matrix Cannon and Vanguard Booster, from the combination of the Red, Blue, Green, Gold, and Purple Mini-Con Teams.

IDW Animated comics
Lugnut and Blitzwing each used a Nemesis Shield to survive each other's omega bomb blasts while they were fighting each other for some reason or another. The fact that they both had exactly the same super-weaponry finally clued them in that they'd been had by Swindle, who was supplying both of them with fantastic (and expensive) weapons and cures for their effects.

Transformers (PS2)
After the Autobots had collected all of the Mini-Cons stranded on Earth, they learned that Cybertron was being threatened by the chaos-bringer Unicron. The Mini-Cons merged to form three incredibly powerful weapons, including the Nemesis Shield, and the Autobots were able to destroy Unicron and end the threat to their planet.