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 [Dark Neostorm] [DANE-EN000] | Gear Gaming Bentonville](http://bentonville.geargamingstore.com/cdn/shop/products/189354_200w.jpg?v=1570625925)
