Checkpoint

A checkpoint, first introduced as a lamppost in Sonic 1, will save the player's progress through a level—the player can restart from that point if they die. Checkpoints also serve as the entrance to a special stage in Sonic 2, and the entrance to a bonus stage in Sonic 3 and Sonic & Knuckles.

Sonic 1 Lamppost

In this very first Sonic game, Sonic runs past a lamppost, causing the color of the bulb to change from blue to red. The bulb uses the same palette line as Sonic, and the pole uses the same palette line as rings.

Sonic 1 Arrow Monitor

In the 8-bit version of Sonic 1, monitors are used instead of lampposts. Destroying the monitor has the same effect as touching a lamp post.

Sonic 2 and Sonic 3 & Knuckles Star Posts

These look quite similar to Sonic 1's lampposts, except the bulb is replaced by a star disc and the pole design is slightly different. When Sonic runs past the star post, the disc starts flashing and (if you have enough rings) a torus of stars appears which you can use to enter a special stage or bonus stage.

Sonic Adventure and Sonic Adventure 2 Lampposts

Both games use a redesigned versions of the 16-bit version Sonic 1 lamppost; in these games, two double-lampposts are bent at 90-degree angles, with their tops touching each other. Running through the double-lampposts causes them to spin quickly and bend to a standing straight-up position.