Dingy mice

Dingy mice enter the battlefield with X +1/+1 counters.
Any spells with effect "Destroy", "Deal damage"
or "Exile" casted on Dingy mice will only put
-1/-1 counter on them instead.
{g}: Put +1/+1 counter to Dingy mice.
"Our cat can deal with them easily!"
"Sir, nobody's seen your cat over a week..."