I'm back ! ... I'm very late for this contest. I hope I have enough time to finish my entry.

I just finish the alt-mode art. Boombox is a truck with a trailer. The truck itself transform into a robot. Classic. But I have another idea for the trailer  

So this is the vehicle mode and some refs I use to do that !

 

i think i know what idea you have. The trailer has all those subwoofers and speakers in it.

 

It's a bingo lol

So I finish the robot mode. Mix between G1 / Ongoing / movie style.