Luna Eclipsed is the fourth episode of Season 2. It also marks the return of Princess Luna after being gone for 1000 years. It also marks the return of Zecora from episodes 9 and 10 in season 1. It also marks the debut of the holiday Nightmare Night held in honor of Nightmare Moon. It also marks the debut of Pipsqueak.
Related ThreadsLuna Eclipsed - Episode Discussion (Spoilers) - last post by @ Feb 6, 2012
The Death of Princess Luna -- (Complete) - last post by @ Jul 25, 2012