Youkiki

Youkiki is an instance of Enemy Discoloration, specifically for the Ukiki. Youkiki resembles the original, although it’s fur is now colored gray and it’s skin is now colored blue. Youkiki acts the same as their non-personalized variant, however once they acquire Mario’s Cap they will transform into a duplicate of him and begin attacking. This mechanic is very reminiscent of what Yoshi can achieve in Super Mario 64 DS.

Youkiki is fairly rare to see in a personalized game, and mostly coincides with Dynamic Level Rearrangement for Tall Tall Mountain.

Behavior
Youkiki acts identical to their non-personalized counterpart, trying to steal Mario’s Hat whenever it detects the player. The only exception to this is that Youkiki will deal one slice of damage to Mario when it steals his hat.

Once Youkiki steals Mario’s Hat it will transform into an altered version of Mario, with a brown hat and sleeves, purple overalls, and gray shoes. There is no transition animation for this change. The frame after Youkiki successfully steals the hat, it will already be Mario. This is likely due to there being no animation programmed in, or simply the general bugginess that changes from the Personalization A.I. are known to exude.

When Youkiki is transformed to look like Mario, it will begin to attack the player. It’s attacks are copied directly from Mario, mostly consisting of punches, kicks, jumping, and ground pounds. Each attack does two slices of damage, with the exception of the ground pound which does three slices. Youkiki is able to traverse the entire level to pursue Mario, but it’s movements are not as precise as the player’s. If it falls off a ledge, it will jump back onto the stage in a similar manner to Big Bob-Omb and Bowser.

Youkiki can be defeated after three hits, and will explode into a puff of smoke similar to other enemies. When defeated it will also drop Mario’s hat, although some Players have reported Youkiki dropping three Blue Coins in addition to the hat. However, players have reported rare instances where Youkiki would drop a Power Star alongside Mario's hat. This could be evidence that Youkiki was once part of a scrapped mission.

Adaptive Difficulty
In all likelihood, Youkiki appears due to the Personalization A.I.’s attempt to make a more difficult game for players who aren't being challenged enough. The Youkiki could be considered a ‘miniboss’ of sorts, considering that:


 * There is only a single instance in most personalized playthroughs
 * It’s attacks are much more complex than most normal enemies
 * It requires three hits to defeat

Ukiki's Original Purpose
Some players believe that Youkiki was actually the original intended use for Ukiki, as in the base game Ukiki stealing Mario's hat is fairly inconsequential and easy to retrieve considering he does not leave the small area where he is found. Youkiki could have been part of a scrapped mission, where the player would need to defeat him to not only retrieve their hat, but to obtain one of the game's Power Stars. However this was likely removed either because the boss fight was too difficult, or Youkiki's movements were too complicated to implement fully.

Trivia

 * The mechanic of Youkiki turning into Mario after stealing his hat is very similar to a mechanic in Super Mario 64 DS, where Yoshi can become any of the other three playable characters after obtaining their respective hat. Youkiki was likely the inspiration for this mechanic.
 * The idea of an evil Mario is reminiscent of Shadow Mario in Super Mario Sunshine, however Youkiki being the inspiration for this as well is, while not impossible, fairly unlikely.
 * The idea for an evil doppelganger for Mario in general likely stemmed from Dark Link, who first appeared in Zelda II: the Adventure of Link on the Nintendo Entertainment System. Dark Link could have inspired Youkiki, Shadow Mario, or even both.