a classic with an edge to it:
not only the floor can be lava

movers: move from "important bridge" to "hipster part of the city". try not get burned by the lava. if you are, send the sewer a picture of the lava.

sewer: decide what is lava (an object? a name? a type of building?...) and communicate this to the mover(s) before they start.

the goal is to collect as much lava as possible without burning yourselves too much.
bring it to the lava deposit somehow.
possible soundtrack
I need a map for this