Macy's Green Stars are balloons, which are exclusively used the Macy's Holiday Parade.
History with the Macy's Parade
The Green Stars were first used in the 2008 edition of the Macy's Holiday Parade at Universal Orlando Resort, replacing the Red Macy's Stars. The balloons bookended the event and were made up of the basic Macy's Star balloon base. Unlike most Macy's star balloons from this time period, the text on the balloon was much more fine and thin. This would be changed in 2010 when a bolder "Macy's" font was added to both balloons. These balloons would appear in every year's edition of the Holiday Parade until 2013 when they were replaced by the White Macy's Stars.
The following year, in 2014, new Green Star balloons were created and were the first balloons to use the current Macy's star balloon base, with more vibrant colors, and the return of the finer text. The balloons, alongside everything else in the Parade, was retired after 2016 in order to make way for the re-branding of Universal's Holiday Parade Featuring Macy's. It is unknown if these stars will be used again as part of the main Parade in the future.