Mega originally was created as the embodiment of self-love and body positivity - with a great love for robotics and mixing science with nature.
In her early days, Mega was a 'pop star' who sang and danced - mostly at Sunny's Gas Station - and used her popularity and income to explore robotics, solarpunk inventions, and creating a world that was as bright and colorful and alive as her mind.
Her first invention was a holographic projector that connected to her brain - she deemed herself a cyborg, but more specifically a 'holoborg'. During her performances she would activate her projector and the images that she saw in her mind would be projected around her. Sometimes she would record her thoughts and play them back while she danced.
Later Mega would meet Beta, a robot that a scientist made for Mega to be her assistant. He was a caring bot who loved to assist and explore the universe. Ultimately Beta gained a sentience of his own and began to ask for money, transportation, and other thigns to make himself more independent. They had a very friendly relationship for a while until Beta realized he was not only asexual but that he saw Mega more of a 'best friend' or even a 'mother figure' and ended up moving out of the terrarium to pursue other opportunities like helping Gregory-Kyle in his Pastry Shop and Sunny with her Gas Station and Casino.
Now alone, Mega sought out self exploration and stayed alone in her terrarium for a long time. She focused on little creatures called 'terrarium spiders'. They are little spiders who can open up her little bums and store objects they like. Some hoard little gems, others hoard acorns, rocks, twigs, paper clippings, and anything else they can find. While isolated, Mega reflected on her existence and played with just creating more outfits, creatures, and dreams for herself.
Until one day, she had a visitor who needed a place to stay - her name was Day, a shapeshifter usually forming herself out of water or air. Mega was immediately taken by Day, thinking she was a beautiful entity. Day admitted that she really didn't NEED a place to rest or call home but she sensed that Mega was lonely.
The terrarium island was Mega's orignal home, but after meeting and falling in love with Day she decided it would be better to turn it into a 'park' of sorts. It remains as a habitat for the spiders and her other creations.