Sarsaparilla 

In brief, here's his history:
 He was involved in proposing (with Abd) something called Delegable Proxy.  I wasn't involved in that, but I gather that his contributions were perceived as disruptive and he was blocked indefinitely.
 He used sockpuppets to evade this block.
 Eventually, his block was lifted, and he resumed editing openly as User:Obuibo Mbstpo.
 Many of his edits with this account were perceived as very annoying - he opposed all deletion, for example, and would make significant changes to policy pages without advance discussion, citing WP:BOLD and WP:BRD).  He also proposed new policies that could only be described as "bizarre", for example allowing people to treat Wikipedia like Myspace if they agreed to put Google ads on their user pages.  Some people wanted to re-block him for this; I continually argued against doing so.
 He created Obuibo Mbstpo, a hoax article about a fictitious Nigerian parliamentarian.  When confronted about this, he fabricated a source to defend the article.  He was blocked again.
 He used sockpuppets to evade this ban.
 He eventually took responsibility for the hoax article and fabricating the source.  Once he did this, I advocated - eventually successfully - for his unblock.
 Once unblocked, he created an article on the Easter bunny hotline a phone number which, while existent, was clearly non-notable.  He was blocked again as a result.  I stated that I considered this block unjustified, but that I wasn't going to exert any energy to get him unblocked, since I was pretty sure he'd created the Easter bunny article in bad faith.
 He used socks to evade his blocks.
 He expressed an interest in appealing his case to Arb Comm.  I told him that if he agreed to edit only the arbitration pages, I would unblock him to do so.  Moreover, I stated that I would advocate for a partial unbanning under those circumstances.  He responded to this by declining my offer and continuing to sockpuppet.
It's true that he's never actually been disruptive in parliamentary procedure articles, at least to my knowledge.  I don't care; he's clearly here primarily to disrupt, and the project needs him gone.