I attended Tymmerie Thorne’s amazing Halloween party the other night, where I saw many totally amazing costumes. I believed mine to be pretty good, but it paled in comparison to most of the others, especially Tym’s iron cage skirt, which must have been rather heavy.
A key theme of the party was, of course, blood. It was smeared all over the floor, walls, oozing from various body parts lying about and especially on clothing. There was even a kind of blood-sprayer on the floor wetting everyone down with the red stuff. By the way, if you haven't yet seen this build, I strongly recommend you take a look before Tym and Jerremy take it down. I especially liked the giant ants that devoured noobs, limb by limb.
While I had blood dripping from the corner of my mouth, I felt more was required in that scene.
Taking initiative during a dance, I managed to create a rather realistic and terribly gross blood spurting effect. It looks like you managed to sever a key artery, and is quite shocking.
If you’re seeking a unique and totally horrifying item for your Halloween outfit, you might consider the Blood Spurter from Electric Pixels! (It's in the very dark Vampire section)