yugioh movie pyramid of light cards Yu-Gi-Oh! The Novelization - Deck Analyses Pyramid of Light Support :

Techno Radar is the most important consistency piece for Future Decks because it can add any two Future Pokmon from the deck to the hand

If the proposed spell is illegal, the game returns to the moment before the casting of that spell was proposed (see rule 720, Handling Illegal Actions).Since the choice of half was what made the casting illegal, it's an invalid choice, prohibited by rule 608.2d above

What you choose on the next floor will be dependant on your game state, but both are good options

2020-01-24 Players can't attempt to remove Thryx to raise the cost of a spell you wish to cast, but they can remove it to allow their spells and abilities to counter your spells.