Star Post

In the video game series Sonic the Hedgehog, lamppost-shaped items called Star Posts (named by the distinctive star design) were used as "save points/checkpoints" - whenever a character lost a life, he would return to the last Star Post he touched.

Games
In the first Sonic the Hedgehog game, the star posts had not been introduced yet. Instead there were simple lampposts with a blue bulb on the top. When Sonic touched a lamppost, the bulb changed colours from blue to red. These lampposts was only used as checkpoints.

In Sonic the Hedgehog 2, if Sonic or Tails touches a Star Post and has 50 gold rings, a ring of stars appears above it. If Sonic jumps into the ring he is transported to a Special Zone, where he would compete for a Chaos Emerald. In Sonic 3 & Knuckles, the Special Zone would be accessed instead through giant gold rings (similar to how Special Stages were accessed in Sonic 1 and Sonic CD, albeit not at the end of a stage), and the Star Posts were used for accessing Bonus Stages, where characters could collect power-ups such as lives, shields, and rings.

The starposts were then replaced by giant rings in Sonic 3D Blast and became gate-shaped lampposts in Sonic Adventure and Sonic Adventure 2 (because a lamppost would be much more difficult to utilize in a 3-D environment), although retained in its Sonic 1 form in Sonic Advance and its sequels. In Sonic Heroes and Shadow the Hedgehog, checkpoints were red circles on the ground with a yellow star inside them, surrounded by a blue glow. In Sonic the Hedgehog, the two Adventure lampposts reappeared.

Sonic the Comic
In Sonic the Comic, Star Posts appeared frequently in early issues. Star Posts existed all over planet Mobius. They can be activated by Sonic the Hedgehog when he runs around the post at super speed, which creates an energy field on the bulb through which anyone can jump. In this way, the Star Posts allowed instantaneous travel to any other Star Post, as well as access to the Special Zone (which in the comics was an alternate dimension).

As the most common method of access to the Special Zone, Doctor Robotnik attempted to use the Badnik Sonic to destroy the Special Zone when he set up his Special Zone Egg Fortress, but he was thwarted by Sonic.

Following Robotnik's conquest of Mobius, the Freedom Fighters obtained a Star Post for their own use. It was stored initially in their secret underground base, and later carted around with them while they were on the run disguised as Bob Beaky's Travelling Circus. Robotnik eventually succeeded in destroying all of the Star Posts on Mobius, except for the one carried around by the Freedom Fighters and those on the Floating Island (which were used to transport the rescued Emerald Hill Folk to the Mushroom Hill Zone). The Freedom Fighters' Star Post was also used by the Kintobor Computer to separate Super Sonic's Emerald Energy away from Sonic, which caused Sonic and Super Sonic to split into two distinct individuals.

Later, Captain Plunder also acquired a Star Post, which was affixed to the wheel of his new pirate ship. The pirates used the Star Post to travel to the Special Zone.

Adventures of Sonic the Hedgehog
In Adventures of Sonic the Hedgehog, there is an episode when Sonic and Tails are in a car and evade heavy traffic in the road by going into the special stage via a Star Post next to the road.

Archie Comics
In Archie Sonic the Hedgehog, there has recently been the introduction of Star Posts. They are a device built by Rotor which allows Sonic and Tails to enter the former Zone of Silence. After the gathering, it has been transformed into a world which resembles both the special stages from Sonic 2 and Sonic 3 & Knuckles. It is here that the now seven Chaos Emeralds reside.