Probably because it contains more than one type of poisonous chemical. There is a comprehensive Wikipedia article (see related link) - if you scroll down to the Biochemistry section under the Toxicity heading - you'll find a full explanation of the processes involved.
A death cap is a poisonous mushroom. If you eat it, you will likely die.
Mushroom
the mushroom
Mushroom (toadstool)
The 'Death Cap' is the nickname given to the worlds most deadly mushroom, Amanita Muscaria. The greenish-yellow cap of this mushroom is so poisonus, eating it would cause extreme poisoning sickness or death.
It is a mushroom, toadstool, or fungus (fungi).
I think they are of Basidiomycete.
Amanita Phalloides, also known as Death Cap.
Some fruits and vegetables go well in drinks but one that is highly poisonous is the inky cap mushroom. The inky cap mushroom is delicious but highly toxic if added to drinks.
An amanitine is a bicyclic oligopeptide, found in Amanita phalloides, the death cap mushroom, which serves as a deadly amatoxin.
it's called th death cap
The Death Cap and The Destroying Angel are the two most deadliest mushrooms.