The Resonance Blaster is a sonic weapon of Decepticon design.
The Resonance Blaster was created by Decepticon scientists. At some point, the Autobots got their hands on it, and it ended up being stored in the Iacon Vaults. When the Decepticons attacked Iacon, it was launched into space and eventually ended up on Earth. Its landing coordinates were recorded in the Iacon database and years later decrypted by the Nemesis during a moment of consciousness. The Decepticons dispatched Soundwave to find it, and the Autobots sent Ratchet and Wheeljack. Soundwave, distracting the Autobots with Laserbeak, managed to find the relic first, and used it on Wheeljack during the subsequent fight. It dealt with the Autobot well enough that Soundwave was able to collect Laserbeak and take the weapon back to the Nemesis, where Megatron was pleased with his work.
Knock Out borrowed the weapon so he could go fetch an Omega Key. It proved its worth as he took out both Arcee and Bumblebee easily with it before making off with the key. He returned it to Soundwave, who then used it to capture Smokescreen. The Resonance Blaster was apparently with Soundwave when he was trapped in the Shadowzone by Jack, Miko, and Raf, as it was never seen again.
- This was the only relic from the four "Iacon" episodes to not appear in Season 3. It seems to have been misplaced or forgotten.
- Though last seen in the custody of the Decepticons in "Hard Knocks", the Resonance Blaster was never seen again after that episode, and Smokescreen doesn't mention it being present in the vault of the Nemesis during Predacons Rising, leaving its fate unknown. When Soundwave reappeared in Transformers: Robots in Disguise, his arm cannon looked identical to the Resonance Blaster. Since Soundwave was never depicted having an arm cannon in Transformers: Prime, it could very well have been the Resonance Blaster, though it fired standard laser blasts instead of sonic bursts. It is possible, since Soundwave being trapped in the Shadowzone for several years severely weakened him, that his weapon may have also been drained of power by the time he was freed, or the weapon could just simply have multiple settings.