This page notes details of Evilswarm Hraesvelg (DARK/Winged Beast/Effect Monster) : decks, tips, effect and rulings. Learn and enjoy playing Yu-Gi-Oh! Duel Links!
Target an extra deck monster so that it returns to the extra deck instead of the hand.
You can also target a monster that is difficult to summon (like Koa'ki Meiru Maximus) to inconvenience your opponent.
Keep in mind you can also return face-up Spell/Trap cards back to the hand. This might be generally less effective but could be useful in some situations.