If your opponent Special Summons a monster(s) while you control no cards: You can discard this card, then target 1 face-up monster your opponent controls; this turn, that monster cannot be Tributed, or used as material for a Fusion, Synchro, Xyz, or Link Summon. You can only use this effect of "Gnomaterial" once per turn.
![Gnomaterial [DANE-EN000] | The CG Realm](http://www.thecgrealm.com/cdn/shop/products/189354_200w_31f55910-0a8e-4f70-8987-b33666c5a293.jpg?v=1597365336)
