Asterix and the Big Fight

The druid is accidentally hit by a menhir thrown by Obelix and loses his mind and memory.
Gaullish custom requires that a would-be chief must challenge and defeat another to become the leader of two tribes. Vitalstatistix is not perturbed because of Getafix's magic potion. Getafix, however has an accident and forgets how to make it. Then Vitalstatistix is suddenly challenged.