Mortar
At an early point, we played around with some of the larger bots having real pilots - but it made a huge difference to the vibe of the game going from throwing armies of expendable bots at each other to killing manned vehicles.
Early pass on working out a simplified style for our VFX look - Cuevas took this and made a simple version in-game that got used a lot early on
The first really heavy duty unit I designed, and definitely my favourite unit to play with in the whole game. Nothing more satisfying than slowly leapfrogging Mortars across the map.
The initial design just had him kneeling down to go from walking to attack mode, but it wasn't reading super cleanly in-game. We tried a few different options and ended up giving him a more dramatic locked-down mode, and a bigger transformation of the gun from backpack to cannon.
The early version also had an arm on his left side, but it was removed since it complicated his attack mode silhouette and didn't really have anything to do - though I still like the personality it gave to his walk.