Answer: fungus

AnswerCrossword Clue
FUNGUSYeast, for one
FUNGUSLichen co-creator
FUNGUSMushroom, e.g.
FUNGUSToadstool.
FUNGUSPuffball, for one
FUNGUSA growing concern?
FUNGUSDry rot, e.g.
FUNGUSTinactin target
FUNGUSMushroom or mildew
fungusUsed to describe something that has appeared or grown rapidly and is considered unpleasant or unattractive
fungusAny of a group of unicellular, multicellular, or syncytial spore-producing organisms feeding on organic matter, including molds, yeast, mushrooms, and toadstools
fungusFungal infection (esp. on fish)
fungusany of the major group of lower plants