Maybe have a function where you would throw the hunk of stuff causing a little mushroom cloud wherever it hit dealing after burn but it would disable the weapon till it recharged

While equipped, player is vulnerable to many forms of dangerous cancers and tumours

Allied players and enemies will suffer the same within a 100 yard radius

Explodes on first hit
When the explosion occurs, it leaves a lingering cloud of fallout
When enemies are hit by the explosion or cloud, they get Radiation for 10 seconds
Radiation deals less damage than afterburn, but it blocks all healing, makes the screen green and warbly, and slightly damages nearby enemies
40% damage penalty after explosion

knowing valve it'd prolly be a sharpened volcano fragment reskin

irradiates enemies
irradtion
-just a slowing bleed effect
-green cloud icon

The Geiger Grabber: A hammer made of solid radiation!

+ On hit: Causes Radiation for 6 seconds (Any of the radiations described above will do)
+ On kill: Victim turns into puddle of radioactive goo
+ +15% Damage bonus (75 damage up from 65)
- Causes Radiation to self while active (This radiation immediateley goes away when sheathed)

+/- Radioactive puddles cause Radiation to anyone who steps in them (Allies, enemies, and yourself included)

Originally posted by Taco Salad:

Maybe have a function where you would throw the hunk of stuff causing a little mushroom cloud wherever it hit dealing after burn but it would disable the weapon till it recharged

So a sandman that works like a detonator flare for pyro, that's pretty creative actually, I like it.

+Radiation:Surround Yourself with Gas that deal Damage to Enemies the Closer You Are
+20% Damage Increase
-5 Health For Every Second Equipped Unless Radiation is Activated
-5% Movement Decrease