On Plants vs. Zombies Wiki, there was someone called BobbyRio2, a sockpuppet account controlled by the same person who controls SavannahRio2 (links to their userpages are below), and Nathania44 and Nathania1221 are thought to be other alternate accounts.
http://plantsvszombies.wikia.com/wiki/Thread:64304 (This link is a discussion about the Nathania accounts, which was interrupted by BobbyRio2, saying "don't block me")
They were blocked infinitely, but then the BobbyRio/SavannahRio accounts sent me messages on several other Wikis asking me to unblock him on PvZ Wiki, to the point of harrassment (strange how he targeted me out of all the Admins on PvZ Wiki), and I think that BobbyRio and all the other sockpuppets need to be blocked globally, as he will keep harrassing me (and perhaps other Admins on PvZ Wiki) otherwise.
Here are links to his requests that I unblock him, he's messaged me on MANY Wikis, since he keeps getting blocked when he asks for my help.
http://plants-vs-zombies-fan-fiction.wikia.com/wiki/Thread:3789 (This is a request he sent to another Admin, who actually did unblock him, but I reblocked him)