Timehop isn't afraid of calling Facebook out on their, let's say, "Timehop-inspired" new feature called "On This Day."

Timehop is an app that allows users to look back on their embarrassing tweets, statuses and pictures from years past. For their required branded April Fools' Day prank, they announced the arrival of a new app called "Timebook," essentially calling Facebook out on stealing their idea by pretending to steal Facebook's idea.

On the Timehop app, a bit.ly link sends users curious about the joke directly to Facebook's "On This Day" announcement.

That's shade done right, folks.