Exploding Beetle

Reverberation {r} (At the beginning of your
upkeep, you may pay this permanent's reverberation
cost. If you don't, sacrifice this permanent.)

At the beginning of your pre-combat main phase,
put an charge counter on Exploding Beetle.

When Exploding Beetle dies, it deals an amount of
damage to any target equal to the number of charge
counters on it.