The Story of Amy:

Amy ends up to be a new student at Albert Einstein's School. Serena and Amy meet somewhere. Anyways, Luna finds a disk that Amy dropped. Both Luna and Serena look at the disk Amy dropped and find something that clued into Luna that Amy is from the Negaverse. Everybody at Amy's computer class have gone berserk except for Amy. The disks are behind all the madness. After a long time, when Sailor Moon is about to be destroyed, Luna throws Amy the stick that she uses to transform into Sailor Mercury. She uses the stick and blasts the enemy with her famous, "Mercury Bubbles Blast!!!" Sailor Moon then finishes the enemy off by throws her tiara.

Sailor Mercury's Powers

I haven't actually seen all these powers yet because I live in Canada, so I'll just give an answer except I'll rephrase it in my own words.

*SM Powers*

*Mercury Power!*
Amy says this to transform into Sailor Mercury.
*Mercury Bubbles Blast!*
Sailor Mercury says this to generate lots of bubbles that she heaves at an enemy. All it does is make a fog!!
*Mercury's VR Visor*
Whenever Mercury needs to analyze something she taps on one of her earrings and this blue thing goes over her eyes.
*Mercury's Pocket Computer*
Mercury's Pocket Computer is used to analyze things also. You never see her only using just the pocket computer. She always uses both.

*SMR Powers*

*Mercury Star Power!*
Amy says this to transform into Sailor Mercury.
*Mercury Ice Bubbles Freeze!*
It looks like she is going to do the famous, "Mercury Bubbles Blast!" She uses the same background but says different words. and is capable of freezing an enemy.
*Mercury Ice Storm Blast!*
Sailor Mercury says this to generate an ice storm, the ice storm is made out of freezing bubbles, she heaves the ice storm at one or many enemies.
*Double Mercury Ice Storm!*
All it is, is twice the amount of freezing bubbles!!!!
*Shine Aqua Illusion!*
Sailor Mercury spins around creating a freezing attack. She heaves the water at an enemy. Note: This attack looks really cool!!!!!!!

*SMSS Powers*

*Mercury Crystal Power!*
Amy says this to transform into Super Sailor Mercury.
*Mercury Aqua Rhapsody!*
Super Sailor Mercury says this to create an ice harp that blasts the enemy with ice.
*Mercury Aqua Magic!*
This attack is only used once, on the Mercury special, "Amy's First Love," all it shows is Super Sailor Mercury create a ball of ice which breaks into several pieces of ice and reform around an enemy.

Let's see some of Amy's appearances:

Princess Mercury
Sailor Mercury
Super Sailor Mercury
Amy Anderson