Riot Cannon

It's not often a weapon comes along that will make Megatron consider trading in his fusion cannon, but the Riot Cannon is that weapon. Essentially a modified fusion cannon, it fires off high-speed rockets than can really put a crimp in someone's day. With the right upgrades, the last rocket in every clip packs an extra surprise, containing 5 times the explosive power of ordinary rounds.

Transformers: Fall of Cybertron
The Riot Cannon was Megatron's primary weapon during the days leading up to the launch of the Ark. During a brief period when Megatron was dead, Rumble made sure it was kept safe and presented it back to him after Soundwave resurrected their leader.

Transformers: Rise of the Dark Spark
The Riot Cannon is available in escalation along with all the other weapons from Fall of Cybertron.