Instant, U (1) Buyback {3} (You may pay an additional {3} as you cast this spell. If you do, put this card into your hand as it resolves.) Choose a counter on target permanent or suspended card. Remove that counter from that permanent or card or put another of those counters on it.1
Illus. Zoltan Boros & Gabor Szikszai
9/25/2006: Clockspinning can affect any kind of counter, not just a time counter. The type of counter isn't chosen until resolution. Whether to add or remove a counter isn't chosen until resolution.
9/25/2006: If the target is a permanent and it has no counter on it when Clockspinning resolves, nothing happens.