The Twins of the Twins

The Twins of the Twins, as their name suggests, are two more flying mechanical bosses, who are related to the Twins, and spawn with the Twins when World type Chaos, or Just Extremium is chosen. Both modes are chosen as world evils that decreases biome size and requirements greatly, while at a lot of both natural evils for Chaos, and only the Extremium biome for the other, which allows the boss to be fought in both normal and expert mode.

The Twins of the Twins consists of two eyes connected by a single tendril, that will have a connector onto the tendril that connects the Twin. When one of the Twins is killed, the tendril will attach to the single eye left.

Summoning
The Twins of the Twins can be summoned along with the Twins using the Mechanical Eye at nighttime.

Attacks
In their first phase, Unvisiray and Technotinum act similar to the Twins, cycling through 2 attack patterns, Unvisiray will either shoot lasers at the player, or try to charge at the player, while Technotinum will either shoot ichor shots at the player, or charge at the player. When Unvisiray reaches 45000 hitpoints, Unvisiray will change to its second form, when Technotinum reaches 55000 hit points, it will also change forms. In their second form, they will go through 3 phases, Unvisiray, will either shoot 3 lasers at the player, rapid fire half-damage lasers, or charge a death ray at the player, Technotinum will either summon 2 servants at a time, fire a shower of ichor shots, or charge at the player. Each attack lasts for 5 seconds. Damage is doubled in Expert mode.

While the Twins of Twins are alive Boss Music 2 will play.

Tips (secondary modding ideas)
Heavy Metal Hearts are a must, as the 1500 extra health will be crucial in fighting a high damage boss.

Persistence in the Extremium biome despite the extremely difficult enemies, can allow you to obtain the Draconium Set, which has enough defense to reduce some attacks to only 1 damage. (500 def for mod idea.)

The Draconium Sword also deals reasonable amounts of the damage (1150), but has a short range (between light's bane and blood butcherer). A Terrestrial Exploration allows a bit of extra damage (1195), while also inflicting the cursed blaze debuff that deals 150 damage per second.

For Ranged builds, a Giant Bow, or full auto shotgun can take down the boss in a few minutes.

Trivia
Like the Twins, the Twins of the Twins have sprites similar to the Eye Of Cthulhu in their first phase

Unvisiray would've been a portmanteau of "Invisible" and "(Death)Ray," but starts with a "U" to follow the alphabetical order of the Twins, going R, S, T, U

Technotinum is based on the element Technetium, but with the word "not," while also adding a bit of variation.

Despite Technotinum having over a million health in Expert Mode, the Twins are still the Mechanical Boss with the least health, due to only have 2 parts, compared to 5, or 75 for the others.