Bumblebee

In Iacon, before the war, Orion Pax and D-16 get sent to the trash incinerator as punishment, where they meet B-127, a robot who never stops talking. When Orion finds a message from the Prime Alpha Trion, B-127 tags along with him, D-16 and Elita-1 to the surface. With the Primes' cogs, he gains the power to transform too.

Back in Iacon, Sentinel's forces lock him up with D-16 and Starscream. Once free, he helps Orion and Elita capture Airachnid, whose memories show the whole city who Sentinel really is. When Orion becomes Optimus Prime, B-127 stays at his side.

In the live-action timeline, Optimus sends B-127 to Earth in 1987 to set up a base. He crash-lands in California, gets attacked by Sector 7 and fights the Decepticon Blitzwing, who rips out his voice box and damages his memory. B-127 wins and hides as a yellow Volkswagen Beetle.

Charlie Watson, a teen grieving her father, gets the car, fixes it and finds the robot inside. She's the one who names him Bumblebee. By accident, Charlie sends out a signal that draws Shatter and Dropkick. Sector 7 captures Bumblebee and Dropkick kills him, but Charlie revives him with an electric jolt. He beats Dropkick at a radio tower, and Shatter dies when a dam floods. Saying goodbye on a cliff with the Golden Gate behind them, Bumblebee becomes a 1977 Camaro and heads off to meet Optimus.

Seven years later, Bumblebee still can't talk: the voice box Blitzwing tore out in 1987 was never fixed, so he gets by with beeps and movie quotes. He's hiding out with Optimus and a small Autobot team, waiting for a way back to Cybertron. In New York he helps the Autobots go after the Transwarp Key, but Scourge kills him in the fight outside the museum.

In the final battle in Peru, the key's energy reactivates him. Bumblebee comes back in time to turn the fight against the Terrorcons, and the Autobots decide to stay on Earth.

In the Michael Bay saga, Bumblebee takes the form of an old Camaro and gets bought by Sam Witwicky, who's shopping for his first car. Unable to speak, he talks through his car radio. At night he slips away to send a signal that brings Optimus and the other Autobots to Earth.

Bumblebee protects Sam and Mikaela Banes from Barricade and becomes the kid's guardian. Sector 7 captures him along with them, until Sam convinces the agents to let him go so he can get the AllSpark to Optimus. At the Battle of Mission City, he stays by Sam's side to the end.

In Revenge of the Fallen, Bumblebee takes it hard when Sam leaves for college and keeps fighting with the Autobots in NEST. In Dark of the Moon, the two are separated: Sam can't work with the Autobots anymore.

When the Decepticons seize Chicago to pull Cybertron toward Earth, Bumblebee returns to the city with the Autobots. In the battle, he kills Soundwave and destroys the Control Pillar, shutting down the space bridge and collapsing the part of Cybertron that had already come through.

In Transformers: Prime, Bumblebee is the scout on Optimus's team in Nevada and spends the series unable to talk, using only beeps, as in the films.

In the final battle for the Omega Lock aboard the Nemesis, Megatron shoots and kills him. The Omega Lock's Cyber Matter brings him back and restores his voice. It's Bumblebee who kills Megatron, with the Star Saber, before the Autobots restore Cybertron.

In the 1984 show, Bumblebee was a yellow Volkswagen Beetle, voiced by Dan Gilvezan and friends with Spike Witwicky; in season three he gets a new body and becomes Goldbug. Michael Bay's films made him a Camaro because Volkswagen wouldn't allow its car. The Last Knight shows Bumblebee in World War II, but Bumblebee (2018) sets his arrival on Earth in 1987.