In "The Veiled Threat", there is a tiny infiltrator/spy-bot that passes for a crab. It's not named, but it's robot form is described as like Frenzy's, but smaller. At first I thought it was Scalpel/"The Doctor" as he's the only one who's small enough to turn into a crab without mass-shifting. But there's another robot I didn't even consider. One who's size is not only correctly tiny, but who's form resembles Frenzy's more so than Scalpel's. You ready? Spoiler WHEELIE!
Wheelie isn't that small bro, those crabs seemed really small in the book. First book I've ever read that I can say would make a better comic.
I dunno, Wheelie seems to be pretty small, and once he collapses down even more... (Small Wheelie.) And the crabs didn't seem that small to me. Red Crabs can get pretty big. (Big Crabs.)
How about one of Soundwaves spy-bots? Like the insect with the satellite-dish in the trailers? Crabbycon!