omega flowey

It is NOT called "Omega Flowey"!!

It's literally callled "Photoshop Flowey" canonically; https://undertale.fandom.com/wiki/Photoshop_Flowey

The term 'omega' means final, and is the final letter of the Greek Alphabet, that form of Flowey in that fight is incomplete without Frisk's SOUL. So the whole point of the Photoshop Flowey fight is for Flowey to take your SOUL and become godlike.