Al used to be told off by Ed for adopting and hiding kittens in the chest cavity of his armor body. Used to. As in past tense, since the Elric brothers discovered a very original use for their pets.
Ed finally conceded that the cats were indeed very useful.
Only when they found themselves trapped in an alley, with the Homonculi blocking the only exit.
"Nii-san," Al stopped his brother from stepping forward and attempting to fight them off with his transmuted automail. "I have a better idea."
Al ripped off the chest plating.
The Sins screamed in pain as they were swarmed with angry and dangerous clawed beasts.
"Al. You are a genius."