I know a variation of this has been answered before, but here is what I need clarification on:
BBEG1 fights party in round 1, and summons BBEG2 (identical creature, same stats). Party defeats BBEG2, and BBEG1 runs away.
Does the party get XP for BBEG2 (summoned one) or not?
Summoned monsters do not grant XP. They get XP for making BBEG1 run away since you dont have to kill the enemy, just overcome the encounter.