Sonic the hedgehog
The Sonic the Hedgehog series is a video game franchise published by SEGA. The games center on the anthropomorphic blue hedgehog, Sonic (who as the name implies moves at supersonic speeds), who must thwart the plans of the evil Dr. Eggman, a human mad scientist who desires to take over Sonic's world with his robotic creations. In his adventures, Sonic is assisted by numerous friends, including Miles "Tails" Prower, a young fox who can fly by spinning his two tails like helicopter blades, Knuckles the Echidna, the guardian of some of the powerful artifacts of Sonic's world, and Amy Rose, a female hedgehog smitten by the titular hero. Other characters usually act as adversaries to Sonic, including Metal Sonic, a robot built by Dr. Eggman that matches Sonic's speed, and Shadow the Hedgehog, a character who can utilize powerful techniques such as "Chaos Control".
Most of the games in the Sonic franchise are platformers, a genre in which the aim is typically to navigate through obstacles to a goal. The series has differentiated itself from other platforming games with the high speeds at which Sonic and other characters move through their environments. Doing so is aided and hindered by loop-de-loops, slopes, half-pipes, and other features that utilize characters' speed and momentum. Jumping, spinning, and other techniques are also utilized.
Characters also gather golden rings, which serve as protection against enemies and other threats. When Sonic or another playable character is harmed, he or she usually loses all the rings they have accumulated so far, although it may be possible to recover some of them. Take damage without any rings, however, and the player will lose one life, or attempt to complete the game. Dr. Eggman's harmful robotic enemies can typically be destroyed by jumping or spinning into them. In earlier games, Dr. Eggman is usually confronted in one of his dangerous contraptions at the end of differently-themed areas, almost always taking multiple attacks to repel. Another prominent element are the Chaos Emeralds, powerful objects that must be collected to access additional game content or to advance a game's story.
Originally created to help SEGA challenge Nintendo's dominance of the video game market at the beginning of the 1990s, the series continues to this day and has created large amounts of Sonic the Hedgehog-related merchandise, including multiple comic-book series and animated television shows. Sonic the Hedgehog has also been featured as a balloon in the Macy's Thanksgiving Day Parade in 1993 and 2011, as well as being inducted into the video game "Walk of Fame" in San Francisco in 2005.
Due to the series's enduring popularity, it has spun-off into numerous non-platforming games. These include racing games such as Sonic R and the role-playing game Sonic Chronicles: The Dark Brotherhood. Characters from the series have also enjoyed numerous cameos in other video games and mediums, and have prominently featured in cross-overs with characters from the Super Mario Brothers and Banjo-Kazooie video game series.