Trademark troll
In international law and business, a trademark troll is a person or company that attempts to register a trademark illegitimately and then threatens to sue others who use that mark. As a traditional troll is said to collect a toll from those trying to cross a bridge, a trademark troll "magically appears when an unsuspecting producer adopts the same or similar mark and poses upon them two choices: pay to get a license to use my mark or litigate".