>>11463631
Vehicle mode. 80% of his transformation is just getting his arms in place; the rest is folding the wheels out of his chest and tucking the head in, spinning the torso around, and flipping up some panels to hold it in place. Prime's hand transformation is unusual, and I'm not entirely sure I like it, but it does the job.
I like that this is one Prime that can become a literal convoy, having Hot Rod and the Micro Trailer tagging along with him; alternately, you can store Hot Rod in the trailer, then the trailer inside Prime's trailer/right leg (again, keeping his blast effects in his left one), letting you store all of his components nice and neatly. His big gun and little gun both attach to the top, and the shoulder turrets just spin around atop the cab.
He rolls along with no issue, but he's basically a giant brick - since his 'trailer' is just his legs, there's no hitch between it and the cab, meaning no separating the two or having it bend when he turns like an actual trailer would.