@AutoExplode first you place the gas of your choice, then you have to make a blob of soapworm soap (there is a special LUA element i downloaded which makes that easy, you should try to find it, its the soapworm mod) and set the tmp to 0, it has to be on an empty save of the soap will connect to the first pixel placed, which you dont want. if you want to do it on a non-empty save, press "D" and find the pixel number of the gas and set the tmp to that number (example: gass number=50, tmp=50)
it's head looks like a "head". +1