Here is another installment of exTRAPaganza, our Thursday over-the-top trap series.
The entire area is littered with seemingly bottomless pits. These pits are extremely deep (> 400 ft), and all lead to a huge underground pool of a super reactive liquid. Anything dropped into a pit will cause the pool below to explode when it lands 1 round (5s) later. The force of the explosion is > 100d6 and completely seals off the underground complex.