Undead Swarmshifter

Changeling, Menace
When Undead Swarmshifter enters the battlefield Amass 1 and put X +1/+1 counters on either Undead Swarmshifter or target Zombie Army token you control.
When Undead Swarmshifter dies Amass 1.
Swarmshifters are undead who can assume the form
of a swarm of insects or pests.