Although it has been clearly stated by both Getafix (in "Asterix the Gaul") and Asterix (in "Asterix and the Laurel Wreath") that the magic potion does NOT grant invulnerability (Getafix has a potion for that but it is only mentioned in Asterix the Gaul), meaning that they "could" be injured by the Romans in their fights but their raw strength generally prevents the Romans getting the chance to do so, the same does not seem to be true of Obelix. He does not even notice when attackers attempt to knock him unconscious with blows to the head, when Roman spearheads are stuck in his bottom in "Asterix in Corsica" or when anyone else attempts to harm him in any way. This may imply that Obelix, either by stupidity or ignorance, simply does not notice or react to the pain that should be inflicted, or that the potion has enhanced his overall strength, since it has been shown to increase the drinker's endurance allowing them to run faster, to such a point where his muscles allow him to effortlessly absorb the attacks in question. Most of the occasions where Obelix demonstrates invulnerability include him being attacked physically rather than with sharp objects, as in Asterix and the Magic Carpet, when an arrow accidentally hits his bottom and he yells in agony, and thus showing that Obelix isn't above physical pain.