MAMMOTH — Mobile Amphibious Modular Multi-Ordnance Tracked Hulk

When the tank stops mattering and one spidertron isn't enough: a huge tracked fortress for the end game.

A factory floor inside. Step inside and build on a floor of your own, 32×32 at normal quality up to 64×64 at legendary. It needs no electric poles: the whole floor is powered, like a space platform.
Turrets on the floor fire from the vehicle. Gun, rocket, laser, Tesla, railgun and artillery turrets, and turrets from other mods too. Rockets launch from the pods on the turret head, lasers from the projector, Tesla bolts from the mast. Ammunition and power come from the floor.
The chest in the middle of the floor is the vehicle's trunk. Request iron and explosives from your logistic network, make rocket ammunition inside, and feed it straight to the turrets.
Amphibious. It floats low in the water and crawls across lakes, swamps and oceans, with a bow wave and wake. Lava stops it.
Drive it from inside. Take the helm and steer by remote control while you stay on the floor.
A huge equipment grid. Batteries in the grid also power the floor.
Nothing is lost. If it's picked up or destroyed, everyone inside is put outside. The floor, and everything on it, comes back with the next one you build.
Rules: one per world per team. It can't be built on a space platform, and it's too heavy for a rocket: ship the four parts and assemble it on the planet.

Research: 5,000 of every science pack, after promethium. Requires Space Age.