Muscle Flex is a recurring skill in the Dragon Quest series.
Appearances
Dragon Quest VIII
Making its debut, it is used by Hoods in battle to reduce the Tension of all enemies by 1 level each.
Dragon Quest X
Used by Heavy hoods and Robbin' 'ood, as well as Hoods once again prior to the latter half of 2.1, it acts differently from VIII in that it now increases attack and defense for all allies and the user, while gradually recovering HP and MP over the course of battle. However, it is a wasteful action Robbin' 'ood can use when he fights alongside players in the Moon sidequest stories.
Dragon Quest XI
Acting the same as in X, it is once again used by Heavy Hoods in battle, costing 0 MP for them to use.
Dragon Quest Monsters: Super Light
Dragon Quest Heroes II: Twins Kings and Ending of the Prophecy
Used by Hoodlums, as well as Hoods, Heavy Hoods, and Robbin' 'ood once again.
Dragon Quest Walk
Dragon Quest Tact
Used by Robbin' 'ood once again during his boss fight, it increases his attack and defense for 3 turns, costing 28 MP to use.