Necktie Cat is one of the three skins released under the monthly Skin'O'Matic offer. It could be purchased individually using game coins in mid March 2018.
Necktie Cat could be purchased in the Skins Shop under the ‘Skin-o-matic’ tab for 690 coins. This skin was available for a limited time and may not be available for purchase in the future.
Details of this skin may vary depending on location, platform or time.
Note: Necktie Cat was released again for a limited time under the Cats of Agar.io offer in mid November 2019. This time Necktie Cat could be purchased for 3200 coins.