COVID-1993

Tap enchanted creature. It can't untap.
COVID-1993 etbs with X cycle counters on it.
At the beginning of you upkeep remove a
counter, then create twice X tokens that are
copies of COVID-1993, X being the number of
COVID-1993s you control. If there's no counter,
sacrifice all COVID-1993 you control.
"The virus spreads quickly, not harmful enough to be
lethal. Watch out for it's exponential growth!"
Some hysterical mathematician