The marketing hype on this gruesome trick is zany fun: freak out your neighbors! Put it under a sibling's bed!
For a little rubber hand two inches in size (before growing), its visually striking display on this red, black, and white card package makes it irresistible. As well as the little bit of bone sticking out the end, which contrasts nicely against the red stump. How can you pass it up?
For an added treat, the disclaimer on the back is charmingly nonsensical: This toy is in no way intended to represent living people. Any resemblance is purely coincidental and not intended to harm anyone.
I suppose if you know someone who's all thumbs, they may be a little offended.