Roto-Disc

Roto-discs (also spelled Rotodiscs, Roto-Discs, or Roto Discs ) are Fire Bar-like obstacles that first appeared in Super Mario Bros. 3. In this game, 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 Mario or Luigi transform into a Statue Mario or Mega Mario. Occasionally, Duo-Roto-Discs can be found, and consist of two harmful lights on opposite sides.

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 can kill Mario in one hit, sending him back to the beginning of the area.

Super Mario Land also contains enemies that orbit a similar-locking block and share the same attack pattern; their name isn't given, but it is assumed they are Rotodiscs.

Super Mario Land 2: 6 Golden Coins contains an enemy known as a Guruguri in Mario Zone, which behaves in a very similar fashion to a Rotodisc.