Electro, Negatively Charged

Whenever a +1/+1 counter is put on another creature, put a +1/+1 counter on Electro too.

Whenever a +1/+1 counter is put on Electro, create a 1/1 blue elemental creature token with "Whenever this creature deals combat damage
to a creature, tap that creature. It doesn't
untap during its controller's next untap step."