The Cliff of Fangs

I'm not entirely sure I won't change the rolls on this, but here's an idea for a fantastic location.

The Cliff of Fangs

A 200-foot cliff with spikes of ivory sticking out of the cliff face. The spikes resemble tusks and can be removed and sold. They can also be used to climb the cliff without chance of falling under normal circumstances, although cutting off a spike while clinging to another one requires a roll: 5+ on 1d6 means a fall. All of the spikes near the bottom have been harvested, of course.

The problem, however, is that the Cliff of Fangs is not static. When a character starts a climb, the GM rolls a d20 to determine where a new spike will suddenly thrust out of the cliff face (roll x10 = height in feet, 20 means no "fang" thrusts out.) If a character is currently at that height, the character can:

1. Dodge, automatically avoiding the fang, but risking a fall.
2. Risk Damage from the fang (1d6 roll, take 1 point damage on 5+.)

Every turn after the first, the GM rolls again. If any roll matches the first roll, no new fangs will break from the cliff face for the rest of the climb.

Naturally, some abilities, like levitation, flight, or ethereal form, will alter or negate the above rolls.