You’ve just typed “guy kicked in crotch hilarious” into YouTube and expectantly click the first link. The video that’s loading will surely be a justification for the Internet’s creation, but what’s this?

For your minute-long Oscar-worthy clip, there’s a 15-second ad for the new 12-bladed Gillette Supa-Smooth Razor. Then begins the video proper, wherein said crotch is kicked. Yet the lower part of the scene is obstructed by a pop-up telling you to check your testicles for cancer — and you’re a woman.

Thus begins your voyage across the fetid sea that is the Internet, where entrepreneurs ruin everything they touch by trying to make a quick buck. To help you navigate this putrid ocean of failed marketing experiments, I’ve compiled a list of the native fauna. Avoid them at any cost; kill them when broke.

The Countdown: This malicious ad rears its head at the start of your video. It forces you to watch a countdown along with the ad; each passing second is that much closer to the video, and you reason that it’s easier to endure the ad than to click away. The same logic was used during the Inquisition, and to the same effect.

The Evil Twin: This little bugger is a full screen, and it replaces your browser so quick you miss the switch. Dumbfounded you stare at the screen, missing the humor in the latest Ctrl+Alt+Del before realizing it’s an ad for tooth whitener. You shrug and decide the ad is a little funnier.

The Loader: When you left your charger in the dorm and you just want to check Liveleak for like two seconds, this guy pops up in the background and devours your battery life. Sometimes, the Loader doesn’t load, so you sit there while it slows everything else down. During this time, you think about checking your “registry” for “Trojans,” whatever that is and those are.

The Obstructor: This ad is perhaps the most obnoxious. Some moron fresh out of college decides the most original way to sell razors on the Internet is to have them “shave” away the screen. Now I can’t check Fox News; jerk. Do you want the terrorists to win?

The Oh-God-How-Do-I-Stop-It: While watching a video about the natural proclivities of the crack spider, your joyful mirth is suddenly drowned out by a good old “Congratulations! You’ve won!” You rifle panicked through your tabs to find the culprit, but there’s no ad on any of them. After minutes of indiscriminate and futile clicking, you give up and shut down Firefox. Looking around while it starts up again, you catch a brief glimpse of your spouse and children in the corner of your eye before heading straight to Stumbleupon.

The Lower Fifth: Decidedly less funny than the cast of “Mystery Science Theater 3000” but equally distracting, this guy shows up peanut-gallery style about 10 seconds into every YouTube video. During music videos he asks if you want to buy component cables, and during archived Nixon debates asks if you need a bail bondsman. This is the pariah of Internet ads.

The Moving X: Is he in the upper right? Upper left? Maybe he comes in from the side so he’s constantly moving and there’s a chance that you’ll click the ad by accident. The creator of this ad realizes you will care so little about his product that the only way to get you to care is by misadventure.

Free Crap: Never click the free crap. Shooting 10 iPads won’t cause you to win one. Dunking a little cartoon guy doesn’t even yield a humorous animation where he drowns in poetic justice. Instead victory just instantly transports you to the sponsor’s webpage, where after entering your social security number that iPad will be all yours.

The Skipper: Our latent instincts to hit “skip this ad” buttons finally has an outlet; without thinking we all scan this ad for his sole weakness and, like Bard the Bowman, fire our black arrows at the sole chink in his armor. By exhorting us to skip him, the Skipper proves he has the same relevance as senators who only vote “present.”

Imagine if these ads were roommates. How long would you keep the Loader around, when he turns all your lights on and eats all your food? How about the Obstructor, when he steals your clothes while you’re in the shower?

We can only hope Web 3.0 has ads that don’t inspire you to leap through your monitor fists first.