A party horn, also known as a blow-out, blower, noisemaker or a squeaker, is a horn

Horn (instrument)

The horn is a brass instrument consisting of about of tubing wrapped into a coil with a flared bell. A musician who plays the horn is called a horn player ....

 formed from a paper tube, often one that is flattened and rolled into a coil, and which unrolls when blown into, producing a horn-like noise. Modern variations have a plastic mouthpiece, which prevents the swift degradation of the device from exposure to the moisture of the mouth. Often the paper tube contains a coiled up metal or plastic strip that rapidly retracts the horn when you stop blowing on it. Others have a brightly colored feather

Feather

Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds and some non-avian theropod dinosaurs. They are considered the most complex integumentary structures found in vertebrates, and indeed a premier example of a complex evolutionary novelty. They...

attached to the end which vibrates in the outgoing air flow as the horn is blown.