Hero and Monster

Hero and Monster (rough translation of O Herói E O Monstro) is a Donald Duck comic story featuring his masked identity the Duck Avenger.

Plot
There's a crime wave in Duckburg and Chief O'Hara asks help to Gyro Gearloose, who invents a device to detect criminal intentions so the police can find the exact place of the crime. Sadly, it detects even the slightest crime like throwing thrash, so the whole Duckburg police department and the Duck Avenger comes to stop a guy who dropped his bubblegum wrapping and leave the city unprotected from robberies.

Later, Donald gets a call from Gyro asking help, but seemingly a villain takes the phone and claims he will destroy the Duck Avenger. Donald gets in his superhero suit and goes to Gyro's house.

At Gyro's house, the Duck Avenger finds the place was broken by a strong attacker. The Avenger uses a clue tracker that guides him to the basement, and when he goes down the ladder suddenly ends and the Avenger falls, getting knocked out.

When the Duck Avenger awakes, he's tied to a wheel and sees a green birdlike monster who claims to have get rid of Gyro. The monster turns the wheel around to get the Avenger dizzy and then shoots him, but luckily the Duck Avenger is protected by his bulletproof costume. The wheel gets loose and the Duck Avenger gets free, but he still must face the monster and as a last resource, throws him Gyro's crime-detecting device, which causes the monster to turn into... Gyro.

Gyro explains the device got crazy and caused the bad vibrations it had to detect, so it transformed him, and its functions got inverted when it hit him, so the Duck Avenger notices it now produces good vibrations, which could solve the crime wave. It works as the device causes the villains to repent and voluntarily go to jail, but Chief O'Hara is worried because it affects the cops too, who act so nice to walk puppies and give flowers.