just thought id post this to combat your statement...
unfortunately Psilocybin and other similar alkaloids break down rapidly in aqueous solutions. So a brew with mushrooms in it would 1 probably taste like **** and 2 probably wouldn't stay potent long enough for you to drink it (if you dry hopped it in the second carboy then it would be around 3 weeks after that that you would be drinking it)
even with a high alcohol beer, and im talking really high, there isn't enough alcohol present to truly extract the psilocybin from the mushrooms. Making an elixir with say everclear or something similar will result in a much better shot at tripping off what you're drinking (i guarantee it will work muhaha). you probably wouldn't get enough noticeable effects to make it worth while using beer, simply too much water...