I knew some region use Lego ball.
They use it as living victim with aluminum foil.
And they use it as dead victim painting with black color.
If you don't have such balls,
We didn't select a specific store.
However, you can find these on Amazon in your region.
'stainless ball 5cm' Living victim
'wooden ball 5cm ' Dead victim
Of cause, you can use plastic balls, or other material balls.