Sorcerous Poison [Rogue Ability se104]

[Shadow Era]

Credit goes to Fry.

[Orca]

Obvious.

Name: Master of Poisons
Casting Cost: 2
Target: Weapon
Effect: Allies damaged by weapon suffer 2 damage per turn
Flavor Text: "At first it's like a flu"

[N3rd4Christ]

Name: Paralyzing Poison
Casting Cost: 5
Effect: Ongoing: Opponents damaged by your hero are exhausted untill the end of opponents next turn.
Flavor Text: "This will only sting a bit."

[RunDevilRun]

Name: Poison Dagger
Casting Cost: 4
Effect: Target ally dies at the end of your opponent's next turn.
Flavor Text: "Sooner or later, we all have to die."

[Montag451]

Name: Poisons
Casting Cost: 2
Effect: Target ally takes 2 damage at the beginning of its owner's turn.
Flavor Text: They will feel pain like they have never known.

or

Name: Poison Coating
Casting Cost: 3
Effect: When you attack with target weapon, you may exhaust an opposing ally for 1 turn.
Flavor Text: Their limbs grow numb and heavy.

[N3rd4Christ]

Name: Apply Poison
Casting Cost: 3
Effect: Target Weapon: When you deal damage with weapon attached with this ability destroy that ally.
Flavor Text: "Its only a fleshw..."

[Jarred Pine]

Name: Slow Death
Casting Cost: 2
Effect: Ongoing: Allies damaged by target weapon are poisoned and suffers 1 damage per turn
Flavor Text: "Don't mind the smell of your impending death"

[Ringel]

Name: Acid Blade
Casting Cost: 2
Effect: Ongoing: Target weapon gains 2 attack but loses 1 durability
"It only has to strike once anyway."

edit: It is my intent that you could use this on an enemies weapon in a pinch.

[Montag451]

Name: Acid Blade
Casting Cost: 2
Effect: Ongoing: Target weapon gains 2 attack but loses 1 durability
"It only has to strike once anyway."

Oooo, I like this one. Very good theme to it.

[AnAdolt]

Name: Sulfuric Venom
Card Type: Rogue Item
Casting Cost: 1
Effect: 1 Resource: Target weapon gains 1 attack until end of turn. Last Resort—applied weapon gains 2 attack instead, as long as you have no cards in hand.
Flavour Text: A sharp blade's of no use in the hands of a dead man.

To clarify, the effect costs 1 resource. For more info on how Last Resort works, please visit its mechanics page.