1

A large slab falls from the ceiling.

2

A wall crumbles, revealing a new passage.

3

A fissure opens up in the ground.

4

The floor collapses, dropping everyone in the room to a lower level.

5

A doorway or passage out of the room is blocked by rubble or a heavy object.

6

Water gushes into the room, flooding it.

7

The floor tilts to one side, sending everything sliding or tumbling in that direction.

8

A swarm or stampede of creatures rushes through.

9

An object or structure in the room is smashed, causing an explosion of shrapnel.

10

A nearby room or passage collapses, causing a cloud of dust to erupt into the current room.

11

The ground becomes rough terrain (due to debris, cracks forming, etc).

12

A container is smashed open, spilling its contents (could be treasure or a hazard such as oil or broken glass).

13

Characters are separated (by falling debris, a pillar toppling over, etc).

14

A boulder, pillar, or other large object falls and begins to roll toward the party.

15

The walls and ceiling start to buckle and fall apart. The party has a few turns to escape the room before it collapses entirely.

16

The party is buried by an avalanche of loose material.

17

A monster tumbles into the room. It's momentarily disoriented.

18

A sudden tremor knocks everyone off their feet.

19

Several large objects topple over in domino fashion.

20

Structural damage has created a hidden hazard: Roll on "Trap".