So this thing is obviously going to be toxic and probably spray out icky green stuff all over your loved ones. I'm pretty sure the sniper donated his Jarate for this one.

Here's some stats I am thinking about.

+When you use this gun on an enemy, it will damage them 2 health/half-second. Using this gun on them will charge your biocharge at +50% time, but when the enemy has 50% or less health left, it will charge your BioCharge at +150% Biocharge rate.

+When your BioCharge is deployed, it will release noxious gas that has double the range of the Flamethrower and same amount of damage. Enemies hit by the gas will be poisoned and have jarate effect. Poisoning will deal 3 health/half-second and has the duration of bleeding. Poison can be cured with a health increase of any kind. Allies hit by the gas will become 20% faster.

The Manmelter can remove the Poisoning effect for one guarenteed critical hit.

-50% heal rate. (This gun heals half as quickly as the default Medigun.)
-75% overheal.
-10% speed.
-1 health/second.

Set Bonus - The wearer is immune to Bleeding and Poison.