Machine Gun Kelly Wears Megan Fox's Blood in Orb Necklace

Apparently, things got bloody on Valentine's Day for Machine Gun Kelly and Megan Fox ... and they loved it.

The actress and rapper's love day celebration was more odd/unique than yours, as MGK rocked an orb with a drop of Megan's blood inside it. He proudly displayed the first blood Valentine piece on a necklace.

Megan seemed pretty excited about it ... saying, "There goes my heart manifest outside of my body draped in the towering silhouette of a most unusually handsome boy." Pretty damn poetic!

She added, "The journey will likely be perilous but there is no destination without him."

MGK's bloody pendant ain't all that unique -- both Billy Bob Thornton and Angelina Jolie famously wore vials of each other's blood while they were married in the early 2000s.

Didn't exactly work out for that duo, but Megan and MGK are going for it, anyway.