In fiction (any fiction), where do the cassette transformers come from and how do they end up teaming up with their respective boomboxes? I'm sure they all didn't go "Hey, we're just gonna hang out in your chest from now on, if you don't mind."
I get Ratbat (from Megatron Origin?) But how do Eject and Rewind et al end up in this position, and even think this is a good idea?

does that make sense?