A malevolent curse has tainted your Unseen Hands, transforming them into instruments of potent poison and malignant diseases.
Now, in addition to their inherent destructive power, each hand possesses the ability to infect a target with a myriad of rapidly acting diseases upon physical contact. Similar to venom injected through the poisonous fangs of a viper, these diseases will induce severe vertigo, convulsions, muscle paralysis, searing pain, internal hemorrhages, and organ failure within minutes of contact. If left untreated, the target is almost certain to expire within hours. The more the target is exposed to additional hands, the higher the dosage in their system, hastening their demise.
As the user, you are completely immune to the diseases carried by these hands, and you can choose at will whether the hands inject the diseases when in contact with others.