The URL looks like a GitHub link and it crashes Messages for the recipient. It sometimes crashes Messages for the sender, too, in our tests. It looks like the only way to fix the issue once someone sends you the link is to delete the conversation.
👋 Effective Power is back, baby!
Text the link below, it will freeze the recipient’s device, and possibly restart it. https://t.co/Ln93XN51Kq
— Abraham Masri (@cheesecakeufo) January 16, 2018
So far it looks like chaiOS is good for pranks and little else.