Eyeballs look great in Halloween cocktails. Here are a couple of popular ways to make them, if you lack a supply of the real thing: olives stuffed into peeled radishes, and cranberries in lychees.* The former looks like it's been freshly plucked from a shambling zombie, complete with optic nerve - the latter has a slightly shrivelled, half-rotted look to it. Both are particularly effective if served disguised in a smoky cocktail; the fog clears and the eyeball leers back at the drinker... * Both of these ideas are all over the internet, and I found out about them when my color-changing martini appeared on various "Creepy Halloween Foods" lists (dabbled, neatorama, mentalfloss, etc). I concede that it does have a certain mad scientist vibe to it, but it's hardly gross or scary!