Fire
From Growtopia
Fire is like water, it can overlap actual blocks. While Fire can spread to the other blocks, there is a limit of fire per world. Though Fire can not physically can be obtained, a Pocket Lighter or Eldritch Flame can be used to create it.
A Fire Hose or a Water Balloon can be used to put these fires out, but a Firehouse can be placed to stop fires altogether.
This was added in the Firefighter Update, and all items can be bought in the Firefighter Pack
