Prepare to hear Paris Hilton roar this Halloween ... 'cause TMZ has learned she dropped a ton of money on several sexy costumes -- including a Katy Perry-inspired jungle getup.
Our costume sources tell us Paris blew over $5k at Trashy Lingerie in L.A. ... and bought a ton of stuff including a custom made jungle woman outfit like Katy Perry in the video for "Roar."
We're told Paris' other costumes include your standard slutty fairy, slutty princess and of course ... slutty warrior woman.
It's a big change for Paris, who's trying to branch out this year ... after spending previous Halloweens dressed as slutty cop, slutty Indian, slutty nurse, slutty genie, slutty sailor, slutty prisoner, slutty Alice in Wonderland and slutty Robin (of Batman & Robin).
Trick or treat!