This loots, not rummages, which is in the title, so you will discard the worse cards in your hand which may be what you drew too
For that, youll be able to discard any number of creature cards as it enters the battlefield, gaining a number of keyword counters - including flying, trample, haste, indestructible, deathtouch and more - if it discards cards with those keywords
Loose booster packs This is not really a scam, but as mentioned in the section about weighing booster packs: buy individual booster packs at your own risk
But be careful your opponent is trying to do the same thing, and they might have a custom Magic The Gathering card up their sleeve that youre not prepared for
It can occasionally backfire, as the opponent will be able to put the top card of their library onto the battlefield if it is a permanent