Dogmatix is a fictional character, a tiny white terrier dog who belongs to Obelix in the Asterix comics. Dogmatix is a pun on the words dog and dogmatic. In the original French his name is Idéfix, itself a pun on the French expression idée fixe (fixed idea) meaning an obsession. This pun is unusual for a translation in that it is remarkably close to the original meaning and adds to it (by inclusion of the dog- syllable).
Dogmatix is the only main character in the series that is not human. His role is minor in most of the stories, significant mainly as a 'bone' of contention between Asterix and Obelix as to whether he should be allowed to accompany them on their adventures. However, he is often doing something interesting in the background and occasionally fulfills an important part of the plot. In the words of the authors, Dogmatix is the only known "canine ecologist" who loves trees and howls in distress whenever one is damaged. Despite his small size, he is quite fearless. He has drunk the magic potion on a number of occasions, but his favourite treat is to 'chew a bone'.
Dogmatix makes his first appearance in Asterix and the Banquet. He is first seen sitting in front of a butcher's shop in Lutetia, watching Asterix and Obelix go in. He then follows Asterix and Obelix all around Gaul, appearing in nearly every panel of the story until the end. The two men do not notice him until the very end when he finally attracts Obelix' attention at the closing banquet and is given a pat on the head and a bone. He was meant to be a one-off character (hence his leaving the village in the final picture) but he was so effective that it was decided to bring him back.
Thus his next appearance is in the next adventure, Asterix and Cleopatra in which he played a more active role and was given a name. He caused Asterix and Obelix to argue about whether or not he should accompany them to Egypt, but proved his worth when he followed the Gauls into a pyramid in which they were lost and guided them out safely (with the promise of lots of bones).
Like many dogs, Dogmatix is very protective and jealous of his master, especially when he falls for, or is shown affection by, beautiful young women. In Asterix the Legionary he makes very clear his loathing for Panacea with whom Obelix had fallen in love. He shows the same attitude to Influenza in Asterix and Caesar's Gift and Melodrama in Asterix and the Great Divide. However, despite his loyalty to his master, Dogmatix has been shown to side with Asterix in arguments on various occasions, such as in Asterix and the Soothsayer and Obelix and Co.
- The dog uses the Chihuahua mold because there isn't a terrier dog mold.