The species of starfish are mainly divided into "dominant orders", that is, there are obvious marginal discs, sucker in the tube, and maybe no anus. It covers most of the visible starfish. The other is "Echinoptera", that is, there are clusters of thorns in the body and sucker in the tube foot, but there are few bifurcated thorns. I think the starfish you bought at the seaside should belong to the first kind. The landlord should ask the starfish seller to find out.
Most starfish contain toxins because they contain many kinds of starfish saponins, which are toxic. Although the medicinal value of starfish has long been recorded in Chinese pharmacology, it has the functions of calming the nerves, calming the stomach and relieving pain, enriching the intestine and stopping diarrhea, and can also treat epilepsy and goiter. Generally, it can be decocted or dried and ground. However, due to its toxicity, it must be carefully kept or taken at home. If the landlord just keeps the landscape, just be careful not to be bitten by starfish. If you want to eat it, you need to make sure it has been boiled to eliminate its toxicity before you can eat it.