I gotta toad story - better than the centipede story actually.
We have toads on our property. When it rains, a dozen of them hop out of the way of the car as we drive down the driveway. We never thought about them much. One night, our dog all of a sudden had a hard time walking, had a little frothing at the lips, and had a vacant stare (yeah, even for a dog, it was evident that something fucked up was going on in his head). I remembered seeing a dessicated, roadkill toad in the yard recently, looking like toad jerky. Turns out that the toads are called Bufo marinus, and they are toxic. Our dog had found the roadkill and brought it up to the house, getting poisoned and drugged while doing so. He was tripping! Bufos have all kinds of neurotoxins and cardiotoxins, and in some areas (namely Florida) they are very toxic to dogs. We rinsed his mouth out with baking soda, and took him to the vet the next day. It took about two weeks for him to get back to normal - he couldn't get up from lying down and we had to help him up every time. He has avoided toads ever since, thank god. I have to wonder what it was like for a dog to be hallucinating.
Subsequently someone told us about an island resident whose drug of choice was bufotoxin. He would collect the toads and touch them, using increasingly greater doses to get high. One day he was tripping, on a cliff, and tried to fly. He ended up falling, impaling himself on a tree, from groin to chest. He survived, but he's permanently in a wheelchair.