POSSIBLE SPOILER FOR TF ROTF

I'm thinking it would be cool if Megs rose from his watery grave and was like "hey, I better lay low for a while until I can get reinforcements from Cybertron, I better scan a suitable alt mode."

 

He finds a tank, tries to scan it, but his scanner thingy is still busted so he's only able reconfigure his structure to the tank's rather then a complete transformation.

 

How else is he going to turn into a Cybertronian tank? There aren't very many of those on Earth.

Here's how: he like, knows what they look like, and scavenges parts from Brawlistator and anyone else to make his new body. I imagine that the Allspark would figure into this somehow as well.