Ka-Riss, Swarm Overseer

Trample
Swarm (Whenever a creature with Swarm you control attacks, all other creatures with Swarm you control have to attack aswell if able)
Whenever Ka-Rhiss, Swarm Overseer attacks, it
gets +X/+0 until end of turn, where X is the number of attacking creatures you control.
Adapt. Evolve. Consume.