I have been playing this straight for a couple hours, very good game... but at one level, I don't remember which one but my highest stone was 79, I played a card, it was this purple one that stays on your hand combined with negative.
The card turned colorful and the description was a placeholder using fillers like "NaN". Then the board was full of fire and the opponent said something like "W-what was that?" Then the screen turned white... and froze forever