Agebend AU

Agebend AU (also known as Age Swap AU) is an Alternate Universe in which the characters of the Big Four have become age-swapped versions of themselves.

About the AU
The AU first started when somebody thought to age swap the Big Four and other extra characters in fandom, or make them older or younger versions of themselves for pairings and their roles in other AUs. Much like how fans swap their gender, race or "specie" so they could fit in the roles that they give them a bit better.

The four are even featured as nine/twelve year old children for when they are portrayed as Sugar Rush Racers for the Arcade AU, along with swapping Merida's age and with Penny's due to a magic wand that fans place in the Pennida pairing. Hiccup is also an example of this AU, as there are one group of fans that like to use teen Hiccup in the fandom while an other group prefer to focus on adult Hiccup.

Hiccup Horrendous Haddock III
Some fans focus on Hiccup's fifth-teen year old self from How to Train Your Dragon, while there are those that prefer to use Hiccup's twenty year old self from How to Train Your Dragon 2 in the fandom; there are even those that like to focus on the Dragon Rider's eighteen-nineteen year old self from Race to the Edge. It is same with his friends from Berk.

Jack Frost
Jack can have his (fourteen old year) age switched with his sister's, as she becomes the older sibling while Jack is turned into the little sibling; or make him an adult like the other four members of the Guardians of Childhood. Fans have even featured Jack as a baby that is raised by the Guardians.

In some fanvideos, Jamie is used as Jack's child self.

Merida DunBroch
For the Pennida pairing, Merida commonly has her age switched with Penny's due to a magic wand that they both held.

Hiro Hamada
Hiro's age is mainly swapped with Tadashi's, as he becomes the older Hamada sibling. He is even featured as a younger child for the Vaniro pairings.

Tadashi Hamada
Tadashi's age is mainly swapped with Hiro's, as he becomes the younger Hamada sibling.

Vanellope von Schweetz
Vanellope's age is mainly swapped with Ralph's, as she becomes the oldest of the two. She is even featured as a teenager for the Vaniro pairings, along with other pairings and AUs in the fandom.

Wreck-It Ralph
Ralph's age is mainly swapped with Vanellope's, as he becomes the youngest of the two.

Mother Gothel
Gothel is well known in the fandom for using magic to turn back time of her old age so she could become young again. While young Gothel is mainly used in the fandom, there are those that use old Gothel for the fandom's AUs like Snow White & the Seven Dwarves AU, when her true age serves as the Evil Queen's old woman disguise.

Penny Forrester
For the Pennida pairing, Penny commonly has her age switched with Merida's due to a magic wand that they both held and is commonly part of the ship.

Nicholas St. North
While North's "old" age is commonly used in the fandom, some fans however prefer to use his younger self that is seen in the Guardians of Childhood books. Mostly for crossovers, AUs and even in fanwork like fanfiction or fanart.

Articles/Links

 * BH6 AU Ideas | Age Swap