Fire Jet is a block added by Twilight Forest.
The Fire Jet is found in the Twilight Forest's Fire Swamp
Fire Jets are only used in the crafting of the Encased Fire Jet.
To activate the Fire Jet when a player places one down, there has to be a 3x3 hole under the Jet filled with lava, then place the jet in the hole above the lava and wait for the show to happen.
They can also be used to startle others that may be around the area of the Fire Jet.