FOSS gamedev and creative worlds

The Dungeon-Masters are map-killers. Today they destroyed sfan5's house and a part of my light house. We killed them under our houses for two hours. After sfan5 left, a second one respawned in the rest of his house and started devestating it even more.
It has no sense to fight them - they are total mapkillers. The exlosion effect can even kill your chests (locked and unlocked) and so everything what was in it.

:(

Idea:
If the Fireball hits Cobblestone, the Fireball doesn't explode

that was interesting ..they mined out the whole thing..also..maybe they could make it if a block is covered with water it can get destroyed

that's a cool feature the dungeon masters have but with them spawning and destroying, the map as saschakb said will be killed. As in instead of destroyed buildings craetors where map areas where death destruction herds of them covering the world! this is worst case scenario