The Blue Boomer is a very large mortar-styled firework that has a starburst pattern.
Facepunch implemented Fireworks into RUST during the Lunar New Year Update on January 24th, 2020.
Fireworks were available for a limited time through the Facepunch storefront but can now only be acquired through other players selling them on the Steam Marketplace.
Most players appreciate firework shows and understand that your base is unlikely to have much sulfur in stock by seeing your fireworks, making your base an undesirable raid target.
Due to too many fireworks launching at once affecting lower-end systems, Facepunch implemented a limit on the number of fireworks launching at once. Servers now queue all active firework launchers.