Stats:

+airblast is replaced with a waterblast

+waterblast puts out teammates and covers them with water for 7 seconds

+teammates covered in water are immune to afterburn damage

-waterblast cannot push enemies

-25% less range

-20% less fire damage

+waterblast can disable enemy pyro's flamethrower for a second and reduces damage for another 2 seconds.

(suggested by @lndickens )

-waterblast costs 150% more ammo

-30% less afterburn damage

(I don't know if this is too harsh or not)

Description:

This flamethrower is made from a totally legitimately gained fire hydrant and a definitely legitimately gained firehose. The fire hydrant has been modified to be able to dispense both water and air, so the fire mechanism still works. And it’s all professionally strapped together with 100% safe Mann Co brand tape.

And that's my idea. What do you think?