His fusion cannon can convert any small amount of matter into large quantities of explosive nuclear energy. The cannon can fire a blast up to 12 miles and release enough energy to flatten a small town. Megatron can use his internal circuitry to connect the cannon interdimensionally with a black hole, where it can draw on anti-matter as its power source. The blast from this is far greater, but it creates a tremendous strain on Megatron to do this for even one blast.
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