The Universe boss is the final event boss that Odd will add, it has the same hp as Rainbow boss and you can enter the boss battle through Odd_Developer. You can kill it fast with SP:OH, 4 hits of the V move it has, and the boss wil die.
Drops Gaster Blaster, Purple Crown, Bruh Orb, and Winning Medal (edit if anything else). This has been replace by the Sun Goddess.