Roto-discs[1] (also spelled Rotodiscs[2], Roto-Discs[3][4] or Roto Discs[5]) are Fire Bar-like obstacles that first appeared in Super Mario Bros. 3. Rotodiscs are found orbiting gray or red orbs, on which it is possible for Mario or Luigi to stand. Rotodiscs are nearly invulnerable; they can only be destroyed if the player transforms into a statue by using the Tanooki Suit and lands on top of one. Duo-Roto-Discs[6] can also be found, which consist of two Rotodiscs circling the central orb. If the player destroys one using the Tanooki Suit, the other will disappear.
Aside from Super Mario Bros. 3 and its subsequent remakes, the only other appearance of Rotodiscs is in the Mini-Mario course in Bowser's Castle in Mario & Luigi: Superstar Saga. As a throwback to the previous games, they are obstacles that will send Mario back to the beginning of the area if they connect with him.
Super Mario Land also contains enemies that orbit a similar-locking block and share the same attack pattern; their name isn't given, but they behave similarly to Rotodiscs.
* Exclusive to Mario & Luigi: Superstar Saga. • ** Exclusive to Mario & Luigi: Superstar Saga + Bowser's Minions. † Enemy or boss exclusive to the main game. • †† Enemy or boss exclusive to Minion Quest: The Search for Bowser. • ††† Enemy variants differ in Mario & Luigi: Superstar Saga + Bowser's Minions.