First, I discovered that it referred to the Yorta Yorta language and people (Wikipedia redirected me to "Yorta Yorta" from "bangerang," without explanation.)
The Yorta Yorta people are indigenous Australians who traditionally lived around the the junction of the Goulburn and Murray Rivers in present-day northeast Victoria.
Yorta Yorta Family Groups include the Bangerang, Kailtheban, Wollithiga, Moira, Ulupna, Kwat Kwat, Yalaba Yalaba and Nguaria-iiliam-wurrung clans. Their language is referred to generally as the Yorta Yorta language.
Then, Urban Dictionary told me that it was an expletive from the movie Hook, meaning great or killer. In colloquial use, one might say: "That Orangina I got at Whole Foods is bangerang, let me tell you!"
Urban Dictionary offered further elaboration:
The word bangarang is actually Jamaican slang and is defined as a hubbub, uproar, disorder, or disturbance. Used often in the movie "Hook" by the lost boys. For example:
"Yo, that meal was bangerang!"
"Oh word, that chick looks bangerang tonight."
"We're gonna make a bangerang of a party up in here!"
In a major departure, Urban Dictionary also claimed that bangerang referred to a South Amboy football play in which there are 3 players each exceeding 250 pounds in the backfield and run the ball up the middle. For example: "Bouch, Pat, and Dave ran the Bangerang against Keansburg and decimated them."
Moving even further afield, another submission to Urban Dictionary made a dubious claim:
Bangerang refers to when you get into some kind of trouble a week or more after intercourse. The trouble must be a direct cause of having the aforementioned sex. Karma is possible explanation. For example: "No one at this party will sleep with me cause I had sex with a horse on youtube, what a goddamn bangerang."