The tag alias #71082 bike_horn -> clown_horn is pending approval.

Reason: The alias could go either way, and google lists both as valid for this object, but in my eyes clown_horn is better since all of the images under bike_horn use this object in a comedic way associated with clowns. None of the images use it with bicycles.

If you want a more technical name, there's squeeze horn or bulb horn.