Doing a map that has challenges associated with creepy statues in the middle of earth demands some kind of magical effect.
This variant can be used when your players complete challenges or if you really want to stick it to them you could have this effect activate every second round in combat while having your players roll DEX saves. If they fail maybe they take a little damage and burn their feet or maybe they get blasted to high heaven this radiant damage.
Thanks again for your support!