Can be used as an arcane focus. This wondrous abacus has 3d6 (10) beads. As an action, the wielder can take an action to count a creature by moving a bead across the abacus’s rail. Each turn, the wielder can continue to count creatures. As part of the same action, the wielder can slam the beads back to their starting position to cause each counted creature to take a number of d10 force damage equal to the number of creatures counted.

If the wielder doesn’t take an action on its turn to count before resetting the beads, the wielder is added to the count and the beads reset themselves. The wielder takes the force damage in addition to the other counted creatures. 

Notes: Mathmatastic! Can be used as a normal abacus provided creatures are not being counted. An abacus with 10 beads can count up to 19 creatures, 11 beads can count 29 creatures, 12 beads can count 39 creatures, etc.