In the early Cambrian period, the trilobite began its global rule, eventually resulting in 17,000 species of the little critters. I dedicate this key fob to our extinct, chitinous friends.

You know what else there are 17,000 species of? Paracord keychain fobs. So, why would you make this one? It's not only cute; it's rapid deploying! Don't put up with a key fob that takes two minutes to untie. Who's got time for that?

Step 1: Materials

52 inches of paracord, ends melted.
A thing to tie it to, like a keyring or carabiner.

More paracord is always better, but there's a limit on how much you want attached to your keys. For me, fifty-two inches is the sweet spot. So far I have used this length to:

improvise a dog leash
tie out a tent stake
tie down a propane cylinder in the car trunk when I refill it
make a shoulder strap to carry a water bottle
practice knots
improvise a belt
replace a broken shoelace
wear keys around my neck for wading deep water (electronic car key can't get wet)

52" also makes a nicely shaped trilobight.

Step 2: Bunny Ears

Find the middle of your paracord by folding it in half. Keep it folded in half. Poke an inch of the middle end through a carabiner, or your keyring.

Now there's a short middle loop, the carabiner, and the long rest of the two strands. From the "long rest", keeping both strands together, pull a byte through the short middle loop.

This is like doing a two-strand daisy chain around the carabiner, if you know what that is.

Another way to think about it: this is like a simple cow hitch, but just put a bight through instead of all the cord. Like a slip cow hitch.

Uh, maybe just look at the pictures instead. It's pretty simple.

Cinch it down tight. Make sure these loops, hereafter "bunny ears", are 2 inches and even.

Step 3: Weaving

Orient your bunny ears pointing down, and with a strand of the free end hanging down on each side.

This weaving pattern is symmetric, which makes it easy; every weave starts the same way. I grab the left strand, and with the mnemonic "left behind", I always remember to take the left strand behind the left ear. Then it goes in front of the right ear.

Now grab the right strand. Go over the top of the left strand, to bind it down, then go behind the right ear. Go in front of the left ear, and poke it under the strand we started with. Snug the weave tight.

Now just repeat that weave, always starting with "left behind". And again... When you will have only one inch of cord left on each side, go to the next step. You may need to scrunch the previous weaves north toward the keyring to give you a little bit more room.

Step 4: Antennae

To finish off your trilobight, all you need is to take the ends and feed them through both bunny ear loops. First do one side then the other. Those form the antennae.

They are also mission-critical, for without them, your trilobight will unravel.

You are finished!

Step 5: Deploying

To deploy, pull the antenna cords out of their bunny ears (simply reversing the last process).

Without the ends going through the bunny ears, all the weaves can slide off the ends. Help them do so by grabbing the whole outer trilobight, while pulling the keyring in the opposite direction. Any stuck loops can be freed by pulling the bunny ear out of the center of it.

Beware, the cord will not be attached to your keys once you deploy it.

Hope you enjoy this key fob method!