If Craig Boone is no longer on the battlefield when the reflexive triggered ability resolves, use the number of quest counters that were on it when it was last on the battlefield to determine how much damage it deals.

You don't choose a target for Craig Boone's last ability at the time it triggers. Rather, a second "reflexive" ability triggers when you put two quest counters on Craig Boone this way. You choose up to one target for that ability as it goes on the stack. Each player may respond to this triggered ability as normal.

In the rare case where more than two quest counters are placed on Craig Boone because of the effect of its last ability (for example, because of the effect of Doubling Season), the reflexive triggered ability will trigger once for every two quest counters placed on Craig Boone this way.