This enemy has large amounts of HP(~1.6m if you have all treasures from ItF Ch.1 ~ Ch.2) and attack damage(21k if you have all treasures from ItF Ch.1 ~ Ch.2), plus area attack. She is tough to defeat, and when her HP gets to 40%, she increases her attack power by 100%, meaning she deals 42k damage in one hit. She also has long range (350), meaning that Cats like Necromancer Cat or Swimmer Cat won't be of any use against her as they have less range. The only debuff you can put on this enemy is Slow by using Psychocat (365) and Freeze by using Akira (430). When using Uber Rares or Bahamut, good meatshielding is very important for them to avoid getting killed. Almost any anti-Floating or anti-Alien Ubers can make her easier. Cats that can guarantee freeze are helpful try to have at least two out to cripple her attack speed all you have to do is get them to hit and then send out your hard hitting cats and destroy her.
It is strongly recommended to collect ALLanti-Alien Treasures from Chapters 1 and 2 before fighting her. Don't forget that the displayed stats imply you have ALL of those Treasures, otherwise she has a 700% buff in attack and health.
With no Treasures, she has a whopping 3,888,885 HP and 49,000 DMG, making her almost impossible to defeat without anti-Alien Ubers.
With all the Chapter 1 Treasures, she has 2,777,775 HP and 35,000 DMG. Still insanely hard to win. (One-shot kills all meatshields.)
With all the Chapter 1 & 2 Treasures, she has 1,666,665 HP and 21,000 DMG, making her quite tough, but possible to beat. However, this power is the least you can get when you encounter her the first time and you can't get the Chapter 3 Treasures yet. Now we're talking.
However, she will be much easier to beat with all the Chapter 1, 2 and 3 Treasures; she will only have 555,555 HP and 7000 DMG, making her more manageable, easier and faster to beat.
As of update 5.6, her HP has been nerfed by approximately 7.5%, down to 555,555. She has also gained a 5f attack delay.