Dreamstuff

Dreamstuff is literally the stuff of which dreams are made. Somehow, the Martians had leared how to create it in the Dream Realm and can use it to create various objects in their dreams.

This became very important in Martian Dreams, where the evil Raxachk had it hidden behind an impenetrable crystal barrier in the Dream Realm. Raxachk gloated that even if the Avatar should manage to gain access to his hoarded Dreamstuff, using it would be impossible for the hero's imagination.

Raxachk was proven wrong when the Avatar managed to get the Dreamstuff and used it (after some imagination raising) to create a weapon from the present, an M60 Machine Gun. Against this weapon, Raxachk had no chance.