Optimus and Nemesis Prime - in miniature!
These came out a few years back. They are the size of Hotwheels, and represent Optimus Prime and his evil doppleganger Nemesis Prime (aka Scourge.) I think Scourge came out first, followed by Optimus himself, who was a KB Toy Store exclusive.
Based on the larger scale G2 Tanker Truck Optimus Prime who was later revamped and re-released as a new character called Scourge (more on him later) these mini-transformers are unbelievably cool. I think the size and vehicle representations are where Go Bots had Transformers beat back in the eighties. Big Transformers are cool, don't get me wrong, but I wish there was a line out today that provided the variety and scale of the 80s Go-Bots. These come close.
Small, cute, a simple transformation, a close-to-true vehicle representation, and a kick-butt design homage to the original Optimus Prime. What could be cooler?