Palythoa grandis is a large-polyped zoantharian (family Sphenopidae) distributed in shallow Indo-Pacific reef environments, forming encrusting colonial mats with notably large, fleshy polyps that extend conspicuously from the sandy coenenchyme for suspension feeding. Like other Palythoa species, it can produce palytoxin, a highly potent marine toxin with significant medical and pharmacological implications. The species is frequently encountered in reef surveys across the Indo-Pacific and contributes to the benthic community structure of tropical reef flats. Genomic data have been generated for this species and are available in public databases, enabling comparative studies of cnidarian evolution and ecology.