Unlike all other Gauls in the village, Obelix has no need to drink the druid's magic potion, because he fell into the cauldron as a baby, making its effect upon him permanent.
Obelix has a tremendous appetite, and his favourite dish is roast wild boar, which he hunts with Asterix. He gets drunk very quickly if he consumes alcohol. Obelix is kind-hearted, but not too bright intellectually, and leaves to Asterix much of the decisions.
This does not seem to have led to a general practice of infant baptism in magic potion among the Gauls.
Obelix's name is a play on the French word obélisque (obelisk), perhaps suggested by his habit of casually carrying heavy stone monuments around with him.