Fungi force us to reconsider what intelligence even means. It’s an emotive, slippery and in many ways unhelpful word for many people it is synonymous with sentience or consciousness, while at the same time being notoriously hard to measure even within a given species, let alone to compare across the species divide. Many animal behaviourists prefer instead to speak of cognition: the neural processes that govern behaviour. But that generally assumes a brain, or at least a nervous system. Plants and fungi have neither.
