Execute DDoS attacks
Web activity
Hacking
Restrict access
Discover personal information
Frame you for crimes
Sending spam
Determine your general location
IP bans
Phishing attacks
Sell it on the dark web
Connect to your network
Denial-of-Service attack
Employers can track your activity
Impersonate you for illegal activities
Impersonate your ISP
Malware infections
And a bit more