Well to hells are plants of the phylum pseudoanimalia, native to Thanatos.
The well to hell is basically a large hole (About 10 feet wide.) in the forest floor with structures resembling teeth along the walls. The hole is about 50 feet deep, but half of that is a pool of dissolving liquid. The hunting method is simple. The plant waits for an animal to fall into the hole. The plant closes the hole using a leaf which acts as a lid. Inside, the animal is dissolved in the liquid, which is concentrated hydrochloric acid. The plant has tough walls, so the acid does not have any effect on it. The dissolved nutrients are then absorbed into the plant.
This plant is named after an urban legend known as the "Well to Hell", which is about Russian scientists who drill a hole 9 miles into the Earth and find Hell. It isn't true of course, being an urban legend.