There are hundreds if not thousands of amanita's, they do host some of the most deadly species including the death cap and destroying Angels which is what you are referring to, and yes you will get sick well after the fact, feel a little bit better and then crash hard as your liver is liquefied. I think it takes about 2 days for an excruciating death things can be done to save you, including milk thistle extract and other plants which protect the liver, most important would be purging the mushroom if caught in time, and or eating charcoal to soak up the toxins so they're not absorbed, but hospitals have some other stuff they can do.