A balloon on a string, as decorates a birthday party. Generally depicted in red, though WhatsApp’s is pink and Google’s orangish-red.
Commonly used to convey congratulations and celebration, especially when wishing someone a happy birthday.
Microsoft and Samsung's balloons were previously blue; SoftBank's was shown floating in the sky.
Balloon was approved as part of Unicode 6.0 in 2010 and added to Emoji 1.0 in 2015.