Guero, the Time Master

Whenever this creature Atacks, put a +1/+1 counter
on it.
Whenever you play a instant or sorcery spell, put a
time counter on Guero, the Time Master.
Guero, the Time Master gets -1/-1 for every time
counter on it.
Instant and sorcery spells you cast cost {1} less for
every time counter on Guero, the Time master.
"All knowledge is at your disposal, are you willing
to take it?"
-Xaran