Used as an exclamation. Can be used in suprise, or in excitement. Is usually used when referring to something happening to someone else, as in a put-down.
From the phrase "Oh Bust!" which was used when one party would verbally bust on another and the bystander would say "Oh Bust". It has morphed from "Oh Bust" to "Oh Bus" to "Bus" to "Busticle", or "Oh Busticle".
Jeff (speaking to Mike): Why dont you answer your phone, you are lazy as Sanders.