If the calling actor has a Missile state and the target is out of melee range, then it will jump to the Attack state.
If the target is at the same height as the calling actor and 44-128 map units away, then it will jump the Walk state. Otherwise if it is within the melee range it has a 12.5% chance of jumping to the Walk state anyways. If within melee range and the walk chance fails, it will jump to the Attack state.
This codepointer is restricted to Serpent and derived classes.