King Trumpet mushroom does not have base unlike Bunashimeji. You can use all of the mushroom without cutting off. You can chisel off the tip of the base if you prefer. The best King Trumpet has curled cap with white and resilient stems.
These are spores of the mushroom. The mushroom is still alive and fresh even after harvest and packaging. Sometimes they generate spores inside package but there is no problem with the quality of the mushroom. Please feel safe to cook and consume.
Mushroom is 90% water. (Spinach or Cabbage 91-93%) You can squeeze water, and it is very water absorbent, they can absorb the dews within the package. Also, damaged part can deteriorate sooner and wetty.
In rare cases, some people claim that King Trumpet smells like a chemical.
Inside the package, mushrooms may keep growing. As King Trumpet mushrooms grow, all the gills under the cap may open up and some of them develop frilly cap. They are safe to consume.