If you’ve ever wondered how venom kills, you’re not alone.

However, there’s no simple answer. There are various types of venom in the animal kingdom, and they don’t all work the same way. Some types of venom cause the blood to clot up, while others immediately begin killing tissues; in any case, they’re all bad news.The YouTube channel “The Nature of Science” decided to provide this little crash course in envenomation, and it’s incredibly interesting stuff. Professor Jamie Seymour explains how various types of venom work, and he even shows a few of his favorites.

The best part of this video is the experiment.

First, Seymour takes venom from the box jellyfish. Then, he gets a toad.Of course, this would be an unnecessarily cruel experiment with a live animal. The toad is neurologically deceased, so it can’t feel pain or experience any part of this. However, its heart continues to beat.He injects the venom into the toad’s beating heart, and the results are immediate. The heart stops relaxing in between beats, and the heartbeat becomes irregular. It’s unable to send blood throughout the body. Within seconds, the heart stops entirely. Box jellyfish, by the way, are extremely dangerous to humans. A direct sting can kill a human in under two minutes in some circumstances.

Check out the entire video for more information on venom.

This is one of the most interesting educational videos we’ve ever seen. With that said, it does show a toad dissection, so it’s not for the faint of heart (no pun intended).