Ratbat

Ratbat is one of Soundwave's minions & pets, alongside with Ravage, Laserbeak, Rumble & Frenzy. He is a recurring villain in the Transformers franchise.

Generations 1
In the original Transformers series, Ratbat was ne of the several Transformers who transforms into a casette. In the American series, like the other cassettes that turned into animals, Ratbat was not capable of speech, and was likened more to a pet than an equal member of the Decepticon forces. However, in the Japanese series, he and the other cassettes possessed the power of speech, though their roles seemed no different. Ratbat first appeared in The Transformers: The Movie and in the third season of the series, he was often sent on spying missions. However, he also appeared in the OVA Scramble City, which takes place before the movie, but reportedly was made after the movie was made.

Transformers Animated
Ratbat appeared in the cartoon series Transformers Animated & his alt mode is a keytar. Like in the original series, he is one of Soundwave's minions alongside with Laserbeak. Ratbat first appeared in "Human Error: Part 1", albeit only in his Keytar mode. He was used by Soundwave to initiate the final phase of his plot to reprogram the Autobots into Decepticons. In "Human Error: Part 2", he uses his bat mode for the first time to attack Prowl after he got back to normal. He is mostly used in keytar mode to control the Autobots. Ratbat, Soundwave, Laserbeak, and Optimus end up in a guitar/keytar battle and Soundwave gets dismantled after Optimus uses Laserbeak as an axe. as a result Ratbat is destroyed, Laserbeak carries Soundwave's most basic component away to parts unknown, but was not seen to be carrying any part of Ratbat.

Trasformers Age of Extinction
It has been currently rumored that Ratbat will appear in Transformers Age of Extinction, voiced by Kim Mai Guest. Unlike in the original series however, Ratbat will appear as Cyclonus's minion instead of Sounwave's since the latter died in Dark of the Moon.