Hammer is a Dragon like Decepticon Mini-Con who is partnered with Anvil and allied himself with Bisk.
Transformers Robots in Disguise
Hammer and Anvil were part of the group of Decepticons led by Scorponok and Glowstrike. They were teamed with Bisk and sent to the Rumbledome to obtain a sound board during the Rear Axle concert. When Russell accidentally knocked over some cymbals, Bisk sent the pair to investigate what had made the noise, and they naturally returned carrying cymbals, after which Hammer received a zap when he touched the cables which Bisk was disconnecting. In response to more noise, the two Mini-Con started shooting up the place, and an irritated Bisk ordered them to guard the door. They accompanied Bisk as he went to secure the sound board being used for the concert, however their tussle with Bumblebee was brief, as he smashed their heads together and threw them into a lighting rig, which zapped them unconscious. The pair and Bisk were kept in a large cargo box as they were taken back to the scrapyard by Bumblebee and Russell.