If you’re going to be especially scary this Halloween you’re going to have to lay the groundwork now. Otherwise no one in their right mind will ever fall for your painfully funny ruse. Whatever it is, decide it now and stick to it through thick and thin. You and your plan to inciting fear for Halloween now need to be closer that you could ever hope to be to a partner (be that crime, business or other).
Of course the truly fun bit is deciding who you’re going to pretend to murder. What’s your motive? What have they done to you to deserve pretend death? Of course it might be some random person in the street because of the homicidal issues you’ve never quite addressed.
The important thing is that they’ll need to disappear in such a way that people will readily believe that they’ve died. Perhaps you could pay for a loved one to go travelling for a couple of months. Or keep them down a well for a bit. There’s nothing creepy or thoroughly illegal about that.
Then you need to begin behaving suspiciously. Start burning random articles of clothing whilst claiming that you simply don’t want them to fall into the wrong hands. Spout ridiculously elaborate alibis so that people know your precise movements for incredibly specific stretches of time. Try and get someone to discover you rocking back and forth or sobbing. Possibly whilst scrubbing your hands to the bone.
Finally, when you reveal on Halloween that you’re only a fake killer people will totally get the joke. They won’t look at you as if you’ve descended into complete madness based on the lengths you’ll go to just to play a trick. Then they’ll shower you with treats and you can get round to thinking about the funny joke you’ll perpetrate next year.