When Abdahla's Familiar enters the battlefield, flip face up the top card of your library, it gains "Teller {X} ({X}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from the top of your library if its face up, tapped and attacking.) where X is its two less then its converted mana cost"

Teller {1}{B} ({1}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from the top of your library if its face up, tapped and attacking.)