Balaur Bondoc

Dromaeosaur discovered in 2010 from late Cretaceous Romania and described in September 2010's online preprinting of PNAS. Here's an article.

The weirdest thing about Balaur bondoc is that it had double sickle claws on each foot, with the additional claw being the hallux that evolution had modified into a retractable enlarged claw. It also had a reduced and nonfunctional third manual digit, unlike all other known dromaeosaurs.