Twins

The Twins are a Hard-mode boss it should be one of the first bosses you beat in HARD-MODE  it has two stages first one is where it looks like two eye of cthulhu and the second stage is where it looks like a robot (and my opinion is the top when its in the second stage it looks like it has a laser in its mouth)How to spawn it is you need a mechanical eye. How its crafted is 5 iron bars 5, 3 lens and 6 souls of light or it can be dropped by mob or theres a 1 out of 2 Chance that it will say This is going to be a terrible night and it will spawn