Omphalorus nidiformis has been long known as a poisonous mushroom and distributed mainly in Australia. In November 2021, some Indonesian foragers consumed the pleurotoid mushroom in West Java, which they believe as edible Pleurotus, and were poisoned. The current study aimed to reveal the taxonomical position of the poisonous mushroom and record the poisoning event to increase public awareness in Indonesia. Fresh materials were assessed for morphological and molecular information. The morphological description was based on its macroscopic and microscopic characteristics. The molecular and phylogenetic approach used internal transcribed spacer (ITS) 1/2 sequence data. The combination of morphological and molecular analyses confirmed the taxonomical position of our specimen as O. nidiformis (Berk.). Omphalotus nidiformis BO24581 has a pale fleshy pileus with a golden-brown color toward the center of the pileus, with some parts of the lamella turned from tawny to green over time, and globose basidiospores. The BLAST result showed that Omphalotus BO24581 was 99% similar to O. nidiformis, P. lampas, and O. olivascens. The phylogenetic tree confirmed that our specimen was O. nidiformis with 100 BS value. This is the first report on O. nidiformis distribution in Indonesia, and this study contributed to Indonesia’s macrofungi diversity data. Additionally, the poisoned foragers had symptoms of nausea and vomiting, as well as weakness, perspiration, and trembling. Our report indicated the urgent need for mycological dissemination to the public in Indonesia regarding O. nidiformis identification.