Sean Parker -- Dropping $9 Million for Wedding Decorations! [PHOTOS]

If you invested in Facebook, here's another reason to unfriend Fbook billionaire Sean Parker -- he's blowing nearly $9 mil to create a temporary backdrop for his wedding.

We've learned Parker -- who made billions with companies like Napster and Facebook -- booked the entire ultra-swank Ventana Inn in Big Sur, CA for the weekend of June 1st to tie the knot with Alexandra Lenas in an over-the-top wedding with a medieval flair.

To realize his vision ... we're told Sean hired a landscaping company to build fake ruins, waterfalls, bridges, ponds and a gated cottage in the resort's surrounding forest -- where he'll say "I do" in a ceremony fit for a king ... or Hobbit.

All the guests will enter through a $600,000 gate, dance on a $350,000 floor, and they better stop and smell the roses ... because Parker's dropping more than $1,000,000 on plants and flowers!

Throw in a bunch more fancy overpriced decorations ... and grand total for the BACKDROP is $8.6 million.

In case you care ... Sean hired the costume designer from "Lord of the Rings" to make threads for his guests ... and like yarmulkes at an Orthodox Jewish temple ... you can't get in without 'em.

Now the kicker ... the entire backdrop will go in the dumpster immediately following the shindig.