Here is another installment of exTRAPaganza, our Thursday over-the-top trap series.
The passages in here have lava running down through them, coming from a central place with several vents. These vents can be easily stopped, as the lava slowly oozes from them. However, if all the lava vents are blocked, the pressure builds up. After 1d6+4 rounds, it explodes, creating a 5 foot tall wave of lava that washes through the complex.