The fungus kingdom encompasses an enormous diversity of taxa with varied ecologies, life cycle strategies, and morphologies ranging from single-celled aquatic chytrids to large mushrooms.
From the en.wikipedia.org
Protozoa were previously often grouped in the kingdom of Protista, together with the plant-like algae and fungus-like slime molds.
From the en.wikipedia.org
Fungi also have a talent for symbiosis, for establishing cross-kingdom quid pro quos that keep the fungus fed and happy while lending its partner vast new powers.