Antimatter
Antimatter is a powerful energy source, though somewhat unstable. Megatron has the power to tap into a black hole and draw on the antimatter within to use as a weapon.
Fiction
Marvel Comics continuity
Generation 1
Megatron used his power on only two occasions. The first time, he intended to use antimatter to destroy Auntie. His interference became unnecessary when Windcharger and Ravage burst into the room and destroyed Auntie in her moment of surprise. Charged up already, however, Megatron decided to redirect the antimatter to kill Optimus Prime, but was stopped by Windcharger. Raiders of the Last Ark The second time, Megatron wanted to use his power to destroy both Optimus Prime and Ultra Magnus. In his state of mental instability and enthusiastic rage, he'd have destroyed himself, the Polyhex Decepticon stronghold and its inhabitants if Ratbat hadn't ordered for him to be teleported to Earth. Resurrection!
Generation 2
The Ark has an antimatter conversion chamber as part of its power system. All or Nothing!
The Transformers cartoon
Doctor Alcazar created an antimatter formula, which came to the attention of Megatron. Predictably, he wanted it as a source of energy. The doc deleted the formula, but sent it to Chip Chase. Ultimately, Megatron decided that antimatter was simply too unstable to use. Roll for It
