Dimorphic fungi are fungi which can exist as mold/hyphal/filamentous form or as yeast. An example is Penicillium marneffei:
At room temperature, it grows as a mold.
At body temperature, it grows as a yeast.
Several species are potential pathogens, including Coccidioides immitis, Paracoccidioides brasiliensis, Candida albicans, Ustilago maydis, Blastomyces dermatitidis, Histoplasma capsulatum, Sporothrix schenckii, and Emmonsia sp.
Mold in the Cold, Yeast in the Heat (Beast)
Body Heat Probably (Changes) Shape
Blastomyces dermatitidis, Histoplasma capsulatum, Paracoccidioides brasiliensis, (Coccidioides immitis is in parentheses because it changes to a spherule of endospores, not yeast, in the heat), Sporothrix schenckii
The reason this phrase says "Probably" is because there is always an exception (in this case fungi like candida albicans) which change in the opposite direction… to mold in the heat!
