Vulnerabully 

Someone who takes advantage of someone else's vulnerability. Or, one who "bullies" someone else for their weaknesses.

Big Johnny was a vulnerabully. He took away Little Pablo's crutches, so Little Pablo had to crawl back to his house (which is over the fence).

The Vulnerabully took a dump in the manatee who's stomach happened to be open during the classroom dissection.

Vulnerabully by Tehe1337 November 30, 2010