We all know the original cardinal rules of horror movies: you won’t survive if you have sex, you won’t survive if you’re drunk or high, and you most definitely will not survive if you go off to investigate a strange noise. Thanks to Randy Meeks (Scream), fanatics that had taken to screaming, “Don’t do that!” at the screen suddenly had a voice on the screen, verbalizing what they already knew. But it’s easy to tell characters that they should be listening to the kooky old gas station attendant warning them of vaguely ominous danger ahead when we’ve already seen several extras get chopped into tiny pieces by a mad man up the road. Without possessing the omnipotence of the audience, we’re all on equal footing because no one expects to suddenly find themselves in a real life horror movie. That’s a good thing, because the “rules” change from one psychopath to the next, and what kept you safe from Dahmer may not help avoiding death at the hands of The Zodiac Killer. Here’s a look at a few notorious serial killers, and what rules of survival we’ve learned from their terrifying reigns.

Lock Your Doors

Richard Chase, aka “The Vampire of Sacramento”, would not enter homes with locked doors, but took unlocked homes to be an invitation to enter. Chase was heavily into the vampire mythology and drank the blood of his victims along with various animals to support his “need.” He had claimed 6 victims before intentionally overdosing in a prison cell.

Sobriety is Safety

Jeffrey Dahmer was actually banned from a bath house after drugging one victim all the way to an overdose. He didn’t appreciate his sexual partners’ bad habit of moving during the act, and had taken to lacing liquor with sedatives to get that sexy corpse-like feeling. Obviously the victims didn’t expect to get drugged, raped, murdered, and eaten, but think about it: Dahmer had 17 known victims. 17 people made the mistake of trusting a regular looking dude. Keep that in mind the next time you’re hanging with an attractive new acquaintance and they offer to mix you a cocktail.

Unprotected Sex Will Screw You

Maybe this one is a tiny bit of a stretch, but Amelia Dyer is thought to have killed as many as 400 babies–maybe more–during her “baby farming” career. Presenting herself as a loving, maternal figure, she took a one time payment from single mothers in desperate situations (single motherhood was sort of a bitch in the 1800s) offering to give their child a safe and loving home. What she actually did was starve or strangle the babies and keep the mother’s payment, pocketing it as purely profit. Many of the mothers that gave Dyer their child had hopes of one day reuniting with their children, which obviously never happened.

Trust No One

Mary Bell is not technically a serial killer as she only claimed 2 lives, but to be fair, that’s a lot to get done in between Saturday morning cartoons. Bell was 10 years old when she strangled her first victim, a 4 year old. Her second victim was not taken until she reached the ripe old age of 11. We’ve all heard the urban legend about the babysitter receiving strange phone calls from someone inquiring as to whether the babysitter has checked on the children, but what if you don’t want to check on the children because they might be armed?!

Clowns Are Bad and Should Be Avoided

Although John Wayne Gacy didn’t murder people while in his “Pogo the Clown” entertainer personality, he performed many events dressed as a fucking clown and if his victim count (over 30) doesn’t make him a monster, his alter ego does. For all you coulrophiles out there, just kidding! (Psst…everyone else…we know clowns are fucking evil.)

Tourists Are Targets

Charles Sobhraj, aka “The Bikini Killer” totaled over one dozen victims between 1974-1976. His exact victim count is unknown, though most were Western tourists. Sobhraj killed in several countries, and is currently incarcerated in Nepal.

The Mask Doesn’t Always Come Off

The Doodler is a still unidentified serial killer who operated in California in the 1970s, picking up victims at gay nightclubs and bars. Earning the nickname from his habit of sketching them before engaging in sexual activities and then murdering them, The Doodler has a victim count of 14. Three other individuals survived the attacks, although their reluctance to “out” themselves as gay meant there was no trial, and the identity of the killer is unknown.