Thread:TouhouandMarioFan/@comment-26146998-20141016222344/@comment-6268337-20141017105117

Sockpuppetry:

"Sockpuppeting", using another account to circumvent a ban or block, is not permitted. If it becomes known that a user is sockpuppeting, their sockpuppet will be blocked/banned, and the ban/block on the original account will be extended. You cannot create another account under any circumstance when you are blocked, whether you are sorry or not.

So basically, it's creating a second account while the first one is blocked, or creating multiple accounts with the intent of pretending to be different people who could "gang up" on other contributors.

See: Flameampharos97 (puppet master) / Mixeldude19 (sockpuppet).