Alicorn Amulet



The Alicorn Amulet is a mysterious artifact that blesses the bearer with "untold powers", and it is featured in the My Little Pony: Friendship is Magic episode "Magic Duel". It is an amulet worn around the neck that bears the effigy of a red-and-gray winged unicorn, along with a massive blood-red gem.

Function
When worn, the Alicorn Amulet appears to grant the wearer immense power, or perhaps dramatically amplify the wearer's own. Worn by a unicorn, it grants immense magical powers (on par with the greatest unicorn spellcasters), including the advanced "Age Spell", which increases or decreases the target's age. While at first glance those powers could be mistaken for nigh-omnipotence, there are some feats of magic even the Alicorn Amulet cannot perform (such as duplicating a target, let ponies play ten instruments at once, or change a pony's gender). Presumably, such spells don't exist (as Trixie points out that nopony can do those spells).

It is unknown what powers the Amulet would grant to an Earth Pony or a Pegasus. It can be speculated an Earth Pony may receive enhanced strength, and a Pegasus enhanced flight speed and advanced weather manipulation.

When using the Amulet, the wearer's eyes glow blood-red, and their magic gains the same red glow. The Amulet itself also glows red when its powers are channeled.

However, the power of the Amulet comes at a price: the more the bearer uses (or perhaps even simply wears) the amulet, the more it corrupts him/her. The Amulet seems to gradually completely smother all the goodness in the user's heart, while dramatically amplifying the evil. If the wearer takes the Amulet off, they can recover from this corruption, but not immediately (as shown when Trixie remained her corrupted self for a while, despite no longer wearing the Amulet).

Furthermore, it has a "magical lock" making it so that only the bearer can take it off. Considering that it offers incredible power and amplifies hunger for power, persuading a wearer to take it off is an incredible feat of its own.

Magic Duel
The Alicorn Amulet only appears in this episode. The dark artifact corrupts the resentful and vengeful Trixie into a crazy sociopathic megalomaniac. Empowered by the Amulet, Trixie manages to defeat Twilight Sparkle in a magical duel and enslave the inhabitants of Ponyville. As time goes on, Trixie becomes more and more hateful and even insane under the influence of the Amulet. However, Twilight comes back later and manages to trick Trixie (ironically with stage magic, Trixie's own domain) into thinking that she has acquired an even more powerful artifact. Trixie promptly snatches the phony amulet and discards the Alicorn Amulet, which is snatched by Rainbow Dash and given to Zecora the zebra for safekeeping.

After recovering from the corruption, Trixie seems to be genuinely sorry for her actions under the amulet's influence and displays gratitude for having been freed of its grasp.

Trivia

 * Prior to the episode "Magic Duel", many fans believed Trixie's Alicorn Amulet to have a connection to King Sombra. One common theory is that Sombra was corrupted by it and was so far gone that he gained its power and malevolence permanently, another states he was the creator of it. The Amulet also shares the King's color scheme.
 * The Alicorn Amulet can arguebly be the main antagonist of the episode.
 * It is argue that Alicorn Amulet is somewhat similiar to the Mysterious Book, shown later in the fourth season which corrupts Rarity: both Trixie and Rarity became a bit psychopatic, their magic changes its natural color to the object's magic color and they gain omnipotence magic powers.