At the start of the Damage Step, if this card battles an opponent's monster with a Deranged Counter: You can destroy that opponent's monster, and if you do, both players take damage equal to its original ATK, also destroy this card at the end of this Battle Phase
Otherwise, I wouldn't stock up on these for long-term gains, as its now fair game for further reprints
The effect is a trigger effect that negates the attack when it is the target of an attack, changes the battle position of this card, and then special summons Blue-Eyes White Dragon
A stronger issue is when the card represents an actual real-life creature by name but when it is clearly not the same in card and mechanics
Her activated ability costs two generic mana and tapping her, allowing a player to sacrifice another creature
If that creature has left the battlefield, even if it came back, you don't sacrifice it