Feeding Tuxie

Feeding Tuxie is a community name for an anomalous phenomenon in personalized copies of Super Mario 64. Although originally passed off as a model corruption, there is a suggestion of it occurring as an effect of Dynamic Level Rearrangement. Currently, there are no known screenshots of Feeding Tuxie.

Description
Tuxie, also known as the "Baby Penguin," is required in order to clear the Cool, Cool Mountain mission Li'l Penguin Lost. According to a now-deleted Reddit post on r/Mario, Tuxie's model may display odd behavior during missions other than the former. Her model will appear to have her head attached backwards, rotated towards the sky, with her beak stretched open. She hops around instead of waddling, consistently making her signature whining sound even when picked up by Mario. Other than this, as far as research suggests, there is no other function assigned to this anomaly's existence. Bringing her to her mother, regardless of being held or not, will only result in the normal dialogue, Egad! My baby!! Have you seen my baby??? She's the most precious baby in the whole world. They say she has my beak...I just can't remember where I left her. Let's see...I stopped for herring and ice cubes, then I...oohh! I just don't know! Tuxie's look-a-like will not be present while Feeding Tuxie is occurring.

Theorizing
It's quite possible that there was originally going to be a star obtained from gathering objects to feed to Tuxie, due to how well it resembles a bird waiting to be fed by its parent, but was cut in the final game. It is currently unknown if there are any remnants of the star in the game besides the model. The objects that would have been collected may be related to the Toad's Tool 64 Star anomaly.

The Reddit Post
The only remains of the original Reddit post is this screenshot (shown on the right), taken by an anonymous source. It is unknown when this post was made, but was likely deleted due to the hostile reply.