134 STAIRS. The stairs descend thirty feet to Area 54 of Level 6. About halfway down there is a trap activated by pressure on one of the steps. It has a 50% chance of going off each time the stairs are used. A metal cylinder with spikes will swing on a chain out of the ceiling, doing 1d12 damage if it hits.
For adventurers descending the stairs it will hit the first in marching order. They may roll vs petrification to avoid it.
For adventurers ascending the stairs it will hit the second in marching order, unless they are very short, such as halflings or gnomes, in which case it will hit the first row. These adventurers may also roll vs petrification to avoid, but the save is at -8.
The trap has a self-winching mechanism, so it will reset itself 3d4 minutes after being triggered.