QP

Heavy Unit #2: The QP (QuarterPounder 🍔):
The smallest of the tanks in terms of damage, but also nimble enough to pop in and out of dangerous situations.

It was once thought that the Behemoth and Spartan tanks got together and had a baby tank and that the QP was the result of such an event. However, this turned out to be false, it's just a small tank.