I would stalk:
iTore - I'd sneak in while he was napping and paint his face like a storm trooper, leave my telltale token of a Slim Jim wrapper, and run cackling into the night chanting
"I am a leaf on the wind..."
Catlynn - because I know where she lives, wahahaaa...
Jullianna - I'd leave footprints all over her beautiful mounds of snow.
Descyple - I'd leave notes all over his car and home signed by famous and long-dead puritans. Then I'd steal his cap and challenge him to an arm wrestling match.
Lil Christian - she would find strategically placed glutton free cupcakes all over her house for weeks, each having been nibbled on in a progressively more thorough manner until there is no more evidence and she must just assume that I am STILL coming into her house, eating entire cupcakes and leaving without a trace. Forever.
DuchessAimee - I will leave small piles of Phase 10 cards around for her to count and keep score of. Which she will do. Because she knows I am lazy with my brain.
Shouryu - Shour will eventually notice that every weekend he makes 5 jars of soup for the week, but on Monday when he opens his refrigerator there are always only 4. MmmmHmmm. Plus, his rice cooker goes missing and the kitchen smells suspiciously like first-pressing Nam Pla.
MissCris - I will sneak over every time it snows, push all the parking lot snow next door onto her front porch, and use it to make a billion creepy little snowdeer who peep into her windows in silent, frozen judgement.
Ugly - Hmmm... I have been sitting here for 5 minutes and can't think of anything creepy enough to frighten Ugly. Perhaps I shall sneak onto his computer, log into his account on CC and revive 100 threads from 2009, signing each one with a different nickname for his actual name, which I'm not allowed to use in public.
Tintin - I'll sneak overseas and accost Tintin with awkward side-hugs and green beans.
If your name is not listed, it is because my plans for you are too horrifying to relate on a public forum. I don't want to scare anyone prematurely.