hmm.... this sounds like a job for the disturbed and erratic imagination of Alex!

Lets take a look: tornado is a rammer, and a toguh one at that, and therefore we are unable to damage it sufficiently, unless we get well under unable to push it and its doubtful that well be able to outmanouver or out accelerate it. Additionalyl althoguh to a heavy the drum is not a major issue it would decimate a robot of this weight.

The only major place it could potentially be damagedis the tyres, however realistically the only way to get the pwoer needed into a weapon to damage the wheels would be to use tornados own drive pwoer to tear wheels, so prehaps a wedge, with a powerful plate which can raise a sheet of small but toguh spieks through holes in the top, robot drives under tornado, spikes go up and tornado shreds its own wheels tryign to get off.

Basically whatever happens its goign to have to get udner the robot, preferably havign a wedge which goes to a point so that theres less surface area for wheels to get purchased on.

if i come up with any other ideas ill say.