A clear cube can work. They can loosely put it on a grooved base so you can take it off and put it back on. In fact, a square base works best there. The thing is supposed to fill out the whold 4 squares!
A real cube - with dissolved stuff in there and all that - might be unique enough to warrant a special edition, one time only, single figure deal. An Icon that is large rather than gargantuan or colossal. That way, they can charge what they need to for it, and don't have to worry about cherry picking and expensive minis and all that.
It really depends on how much that thing would cost.