Secret

Secrets are a type of collectible found in Super Mario 64. They are invisible objects. There are 5 scattered throughout certain maps. When all 5 are collected, a star spawns. They can be inside of other objects, and appear as coins. In some cases, they were replaced by Silver Stars in Super Mario 64 DS.

Visible Secrets
In some personalized copies of Super Mario 64, secrets are visible. What they appear as vary, with some reporting them as coins or silver stars.