This weekend we had a discussion while playing Boss Monster regarding spell cards.
The scenario that we were having is that one of us destroyed his room during the build phase, forcing the other to discard a random spell card. As a reaction, that guy played the spell card (one that could be played in the build phase) to trigger Liger's Den in order to get a new spell card.
Since the latter used to play Magic The Gathering, he claimed that it was a valid move, as it is a reaction that comes on the stack. The other disagreed and said that it was invalid and he should just discard his spell card and not take a new one.
Was playing the spell to trigger Liger's Den a valid one, or did he just need to discard the card?