An Illinois mother is mourning the sudden death of her 22 year-old son who committed suicide after ingesting a supplement known as “pong pong seed” which he purchased on the internet for just $5.

The Blaze is reporting on the case of Bernard McCalip, a young man who had been bullied for years while struggling with his desire to live as a woman.

His mother, Natosha Anderson, said she was not aware of her son’s depression or suicidal thoughts until she found him lying on the bathroom floor a few weeks ago in their Calumet City home. He had been sick for hours and only admitted in his last moments that he had intentionally ingested the seed which comes from what is known as “the suicide tree”.

“He said, ‘I can’t feel my heart.’ And I said, ‘What’s wrong? What’s going on?’ And he said, ‘I took a pong seed.’ And I said, ‘A what? What is that?’” Anderson told ABC7 in Chicago. “The police, the paramedics, they didn’t even know, no one knew.”

Pong pong seed, or cerbera odollam, which is indigenous to India and southeast Asia, is largely unavailable in the U.S. but has been appearing lately on websites such as eBay. The seeds contain a poisonous substance that disrupts the heart beat, usually fatally.

Researchers believe more people have committed suicide with pong pong seeds than any other plant in the world.

“Cerberin appears to be one of the most lethal agents in this class of medications or natural plants,” University of Chicago Medicine heart-rhythm specialist Dr. Roderick Tung told ABC.

Because evidence of the seed is so difficult to spot in autopsies, it is a popular murder weapon in India where researchers found more than 500 cases of fatal cerbera poisoning between 1989 and 1999.

Unfortunately for McCalip, just one of these seeds caused him to die in agony.

“I’m pretty sure he thought it was going to be easy, but it wasn’t. He died in pain. It was slow, and it was painful,” his mother said.

“My last words to him were I love you, and his last words to me were, ‘I love you, mom no matter what,’” Anderson said. “I don’t know how I’m talking … I really don’t, I really don’t, but I think it’s important. I don’t want my son to die in vain.”

Her desire to spare other families the horror she experienced is what’s causing her to speak out about this supplement which is so lethal and yet easily acquired on the internet - a fact which has many experts worried.

“I genuinely hope this is an isolated incident, but we need to be aware that it could potentially get worse," Dr. Shubhrajan Wadyal of AMITA Health Behavioral Medicine told ABC. "And we have to do everything we can to protect our children.”