While prosecuting individual streamers is rare, downloading via BitTorrent (which 123mkv often uses for large files) is public. Copyright trolls monitor swarms. You could receive a settlement letter from your ISP demanding $500–$3,000 for a single movie download.
To understand why the "123mkv com link" is so volatile, look at the legal history: 123mkv com link
Result: The link you found on a forum last week is almost certainly dead today. Result: The link you found on a forum
Many 123mkv clones force your browser to send intrusive notifications. Even after closing the site, you will receive spam pop-ups on your desktop claiming "McAfee: Virus Found" or "Your iPhone is hacked." These are scareware tactics to make you buy useless software. While prosecuting individual streamers is rare
Scammers know people are desperate for the link. They set up fake search engine results. Here is how to identify a malicious link before clicking:
Disclaimer: This article is for informational and educational purposes only. Discussing or promoting piracy violates copyright laws in most jurisdictions, including the DMCA (USA) and Copyright Act (UK/India). The author does not endorse accessing copyrighted content without permission, nor does it provide functional links to infringing material.