Pyke, the Bloodharbor Ripper

Whenever Pyke blocks or is blocked by a creature with less toughness than power, Pyke gets the Upper Hand against that creature until the end of the turn. (A creature with the Upper Hand against an opposing creature will deal combat damage to that creature first, ignoring First Strike, Double Strike, and block order.)
{u}{b},{t}: Assassinate (Destroy target creature an opponent controls with less toughness than this creature's power.)