"Everyone was egging the guy on. He was taking it way too far, next thing he was taking his clothes off inserting a pen in his an*s," Vexxed told Daily Mail Australia.
Things spiralled further out of control when one of the viewers urged the man to carve another female streamer's initials into his arm.
"He went to the kitchen and brought back a knife. You would expect someone to stop him, but everyone was encouraging him to cut his arm."
A woman can be heard saying "that's so hot" when the man begins bleeding from the knife-wound, while another man is heard bursting into laughter.
Vexxed said he called the police in fear for the man's wellbeing: "He clearly needed help."
Officers soon after attended his house and ended the stream, he said.
The man in the vision has released several other videos declaring his love for the New Zealand teenager.
It is not indicated Poison Ivy was directly urging the man to self-harm.
The footage comes after a man claimed Poison Ivy was grooming unstable men, many of whom burst into tears while begging for forgiveness.
Another YouTuber claimed Poison Ivy reportedly seeks vulnerable men in online gaming communities.
His chilling video shed light on the antics and called for victims to help end them.
Poison Ivy's Twitter account, which has since been suspended, was flooded with 900 images of men around the world declaring their love for her.
Where to get help:
• Lifeline: 0800 543 354 (available 24/7)
• Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• Youth services: (06) 3555 906 (Palmerston North and Levin)
• Youthline: 0800 376 633
• Kidsline: 0800 543 754 (available 24/7)
• Whatsup: 0800 942 8787 (1pm to 11pm)
• Depression helpline: 0800 111 757 (available 24/7)
• Samaritans: 0800 726 666 (available 24/7)
If it is an emergency and you feel like you or someone else is at risk, call 111.
