A Krylock was a beast of pure evil which feeds off of magical creatures, such as Unicorns. It had the head of a cobra and the body of a scorpion. It was also inter-dimensional, meaning that it lived in another dimension. The only way it could come to Earth is if it passed through a dimensional door, which could pop out anywhere at anytime. Because of this, it was impossible to track.
Its home was a wasteland of lava and rocks, possibly the interior of a volcano or a place similar to the Underworld.
The Krylock's scorpion-like tail was where the demon stored its venom. When extracted, it would come out green in color and have a slight glow.
This kind of venom was, according to Fu Dog, a key element to making a successful Portal Spell that can locate anyone when the user things of them and create a portal to the target's location. And indeed, if the poison was omitted or replaced with another substance (such as vanilla), the spell would only create a useless, dead-ended dimensional door.
If consumed by humans and Dragons, the venom would infect those who ingested it by giving them Krylock properties. In most cases, victims would grow fangs, a slithering tongue, pincers, a scorpion tail, sometimes even scorpion legs, and their eyes would become reptilian like those of a snake. They would also gain super strength and start a rampage out of savagery.
Because they are under a magical influence, those who consumed some of the Krylock venom could be defeated the conventional way. Since the poison's power came from the beast itself, it was necessary to first slay the Krylock to avoid harm upon the victims. Once the Krylock was defeated, its venom's effects would disappear, turning everyone who was affected by it instantly back to normal. The victims would also have no recollection of ever being under its influence.
Ironically, the Krylock's demise was its own poison, driven through its heart from its scorpion tail by Jake.
- The Krylock Demon was one of the Top 13 Threats to the Magical Community.
- The Krylock was apparently so evil that even its hologram would try to attack people (like Spud). It was even shown eating a harmless Leprechaun in a single bite.
- Victims of the Krylock poison would still have the ability to talk, though most would just hiss and roar.
- When infected by the Krylock's poison, Haley was seen spitting some green and glowing goo that burns through a picture frame like acid. It was unclear if this was a Krylock ability or just an effect of its venom.
- One victim of the Krylock venom developed a tongue with a secondary mouth, a reference to the creatures showcased in the "Alien" movies that have this same property.
- Although the Krylock lived in a world of lava, it was vulnerable to fire.
- According to Spud, the Krylock was a male.
- Unlike most magical creatures, the Krylock was a made up creature in the show, like the Avemetrus, the Shade Demons, the Moss Monster, etc. The other magical creatures like Unicorns, Pixies, Trolls, and Leprechauns are actual creatures that are legendary in the show and real-world.