Asterix: Asterix and The Big Fight: Album 7

now a major Netflix animated series

Gaul was divided into three parts. No, four parts - for one small village of indomitable Gauls still held out against the Roman invaders. 

The Romans persuade a Gaulish chief to challenge Vitalstatistix to single combat. This poses no threat until Getafix is hit by a flying menhir and forgets how to make the magic potion.

Book 7 in the bestselling series.