Game! - Where the stick is mightier than the sword!

Yeah, I thought that was how it would work too after reading the name. Damage would probably have to be adjusted, or like you suggest getting a "percentage of the percentage" added to your health.

Here is my suggestion for the Blood Sucking Alien pet.

How about when he sucks the blood of your enemy, the hit points he sucks are transferred to your character's health? That would be sweet.