Mycogone cervinus    attacking  Helvella lacunosa

The fleas have fleas!   There are many fungi that specialize in  parasitizing other fungi.  Species of the order Hypocreales in the Pyrenomycetes (or their anamorphic (conidial) states) are particularly adept at this.  Mycogone perniciosa (click here) attacks mushroom hosts and can be a serious problem in commercial mushroom culture called wet bubble.     This is a real problem because you can't hardly control a fungus attacking a fungus with a fungicide!  OR CAN YOU!!!!   Students - check it out.