You have found a secret door!
Several items are lying here.
Suddenly a stone block hits your head!
The uncursed pick axe on the ground is crushed!
The uncursed climbing set on the ground is crunched!
The thieves picks on the ground are crushed!
The bone on the ground is broken!
....
At least I had time to detect item status before the block crushed it all.
Edit:
I guess the correct move in the future is to kick all that stuff off the spot.