The danger Spider poses is likely not in actual violence, but if allowed, they will take over your life and destroy you mentally, emotionally, and financially. They will lie, pretend to not be themself, stalk you. They will find your IRL phone number. They will bypass blocks. They will find your other accounts. They will convince you they have changed, including months-long efforts, only to almost immediately drag you right back into abusive patterns. They will purposefully befriend your friends and then lie to you about those friends and to those friends about you to isolate you and make you dependent on them.
The kind of danger Spider poses can’t be understated - when someone stabs you, there is a clear line that’s been crossed. You can prosecute them for assault. You can go to the hospital.
What Spider does will stay with you for the rest of your life.
Following them on tumblr or bluesky or whatever is fine. As far as I know, they have vaguely progressive and positive takes on social media. The danger lies in being friends with them, and especially in letting any kind of sexual or romantic entanglements happen. Do not engage. Do not DM with Spider. Don’t go to a Discord with them in it, or invite them to yours.