Hedgehogs are an abundant species on Mobius, with several important characters being one. The usually nocturnal mammals are characterised as being timid creatures that are covered in spines. These quills come in handy when the hedgehog rolls into a ball, making it largely safe from predator attack. Hedgehogs are commonly found in leafy areas of Earth, but are known to hibernate in the winter.
Of course, on Mobius, hedgehogs are very different. The most famous is Sonic the Hedgehog, a blue hedgehog blessed with extraordinary speed. He is good friends with Amy Rose, a pink hedgehog with a keen crossbow aim and an attitude. These two comprised two-fifths of an early incarnation of the Freedom Fighters and protected the world from Doctor Robotnik. Unfortunately, in times of great stress, Sonic can change into demonic hedgehog Super Sonic who is hell-bent on causing as much destruction and misery as possible. Robotnik has also fashioned two of his strongest robots, Metallix and Metallix Mark 2, in his appearance, and so can be counted as hedgehogs.
Sonic the Comic Online has expanded the roster of hedgehogs, the most significant addition being villanous Shadow the Hedgehog. Originally a discovery by Doctor Kintobor, Shadow was completed by using Sonic's DNA and thus became a hedgehog. Despite being partially made up with Sonic's genes, Shadow was the opposite, completely destroying the Special Zone and almost doing the same to Mobius. Aside from Shadow, Grimer built the Neo Metallix to fool the world into thinking Sonic had become a terrorist, before attempting to kill him. Artist cameos also made a couple of appearances; two hedgehogs were enjoying a picnic in Just Like Old Crimes when Tails plummeted through a tree. An Amy fan appeared in The Battle For Mobius dressed exactly as Amy once did. Finally, a hedgehog character was seen to be arrested in Journey to the Crossroads, having just been beaten by Tails in front of a large crowd.
An Earth version of a hedgehog was also seen. When Amy and Tekno the Canary landed on Earth for directions, Professor Cratermass pointed out that Earth hedgehogs looked very different, much to Amy's distaste.
Silver the Hedgehog was recently seen coming from a far and ruined future which was destroyed by Iblis, a future form Super Sonic seems set to take.