The Master of Time

After Star Swirl returns to Equestria from the past using a time spell, he creates a residue tunnel through time which merges history.

Transcript
(It starts with Celestia looking through Star Swirl's wing in the library)

(A light flickers, Celestia turns around & is shocked to see Star Swirl)

Season 1
Friendship is Magic


 * Nightmare Moon (She notices the portal & goes through causing Luna to disappaer. However, she dies of hypnothermia & her power is drained)

Griffon the Brush-Off Boast Busters Swarm of the Century Call of the Cutie Feeling Pinkie Keen Stare Master A Dog & Pony Show Over a Barrel
 * Manticore (Same thing, but starts to attack Ponyville. However, he has the same fate.)
 * Gilda (Same thing, but before apologizing to Pinkie about her behavior before she & Pinkie dies)
 * Ursa Minor (Attacks Ponyville, but get frozen)
 * Ursa Major (Same thing, same fate)
 * Parasprites (Attack Ponyville, but die from the lack of food)
 * Diamond Tiara & Silver Spoon calling the CMC blank flanks which pisses them off causing all 6 to be frozen
 * Hydra (Same thing, but it collapses from the cold)
 * Cockatrice (Turned Fluttershy into stone but dies as the blizzard gest worse)
 * The Diamond Dogs (Forced out of the caves because of a cave-in & die in the blizzard)
 * Appleploosa freezes, killing Braeburn