From Dragon Quest Wiki

Clang is a spell introduced in Dragon Quest Monsters: Joker. It costs 2 MP to cast and protects the user from all attacks, spells and abilities for one round. It can be learned from various skill trees.

Dragon Quest Monsters: Joker[edit]

Clang can be learned from:

Dragon Quest Monsters: Joker 2[edit]

Clang can be learned from all the skills it could be previously, as well as from Rigor Mortex for 50 points.