Destroy all artifacts you don’t control, then exile the top X cards of your library, where X is the number of artifacts that were put into graveyards from the battlefield this turn. You may put a creature card exiled this way onto the battlefield. It gains haste. Return it to your hand at the beginning of the next end step.
Anzrag's Rampage counts the number of artifacts that were put into graveyards from the battlefield this turn for any reason, not just ones that were destroyed by Anzrag's Rampage. This includes any artifact tokens that were put into graveyards from the battlefield this turn, such as Clue, Food, and Treasure tokens.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.