Miley Cyrus' Dog Tattoo -- Miley Got Inked At House Party For Dead Dog, Floyd

Miley Cyrus will never forget her deceased dog ... because it's now emblazoned on her rib cage.

Miley inked the memoriam Saturday at a house party in Los Angeles. For some reason ... her good buddy Wayne Coyne from The Flaming Lips and another friend tatted the same design in honor of Floyd -- an Alaskan Klee Kai that died when he was only 2.

Floyd's death ... along with a bad reaction to antibiotics and hard partying ... led to Miley's meltdown earlier this year.

It looks like Floyd's mug is the centerpiece of the tat with the words, "with a little help from my fwends."

We'll always remember Floyd ... because we have to now.