Weak Armor

 is a Pokémon ability introduced in the fifth generation. The Pokémon with this ability get faster with attacks.

Description
Pokémon with Weak Armor increase their speed with every physical attack. In generation V and VI, every physical attack only increased speed by one stage. In Generation VII, this was improved to 2 stages. If a Pokémon with Weak Armor is hit with a physical multi-hit move, they will get speed increases for each hit.

Pokémon with Ability

 * Roggenrola
 * Boldore
 * Garbodor

As a Hidden Ability

 * Onix
 * Omanyte
 * Omastar
 * Kabuto
 * Kabutops
 * Slugma
 * Magcargo
 * Skarmory
 * Dwebble
 * Crustle
 * Vanillite
 * Vanillish
 * Vanilluxe
 * Vullaby
 * Mandibuzz

Trivia

 * Stamina works similarly to Weak Armor except for being for Defense and applying to all attacks