The ink cap I know, they grow on buried dead wood I believe. The edge of the cap turns liquid and drips black when they are mature, quite tasty when young, but be careful, the poisonous fungi are ones that grow in those sort of conditions, ones that grow in open meadow land are edible on the whole, though there are some psilosybins that may give you hallucinations they won't kill you.
When the Bank of England was printing the first five pound notes they included ink caps in the ink mixture, but kept the recipe secret. It meant that the spores could be seen under magnification, though people were unaware what they were, and forgeries detected.
Let them grow, they do a good job breaking down material and making nutrients available, and the main part of them is the mycelium, a fine web of threads that can extend over quite an area and will usually reproduce if you divide it, the bit above ground is just the fruiting body, so actually getting rid of them would be nigh on impossible