Toad

Toad is a recurring character and species in the Super Mario series. They are the citizens of the Mushroom Kingdom and faithful understudies of Princess Peach. They will often assist Mario on his adventures to stop the evil Bowser, although most of them show cowardice in the heat of danger.

In Super Mario 64, Bowser traps the Toads in the castle walls, and only a few Toads appear in the rooms to assist Mario. Three Toads will grant Mario a star for talking to them, having hidden them from Bowser's clutches.

Dialogue Phenomena
Any given Toad's dialogue may differ from copy to copy. Most of these changes are barely noticeable, involving different choice of words or grammar to mimic the player's own speech patterns. On some copies, however, a Toad's dialog can range from a completely different message to downright demonic. This often serves as a warning that the copy is heavily personalized, similar to the White-eyed Chomp.

Castle Courtyard
Sometimes, when in the Castle Courtyard, a Toad may appear standing next to the Eternal Star Statue. All players who have talked to this Toad report its dialogue as "help me", "don't save her, please" and "why didn't you save us, Mario?" There is also a single unconfirmed report of this Toad saying the player's real name in place of Mario's. This heavily implies that the Boos that haunt the courtyard are the spirits of dead Toads, presumably buried in the courtyard. The line "don't save her, please" seems to imply that Peach is somehow involved in their deaths.

Ally with Info
In Super Mario 64 DS, a Toad on the second floor tells the player to look for an "ally with info" within the Mirror Room. It's important to note that this is said with every character, including Wario who is unlocked within the Mirror Room, meaning that Toad isn't referring to Wario and it cannot be a simple translation error.

There is also another Theory where the Ally with Info could be the flowers in the Mirror Room, as posted by someone in this comment section!