One-Shot

 is a mid pre-hardmode boss, that you can summon with Snow Beacon in the Stranded Ship biome.

Attacks

 * One-Shot occasionally teleports to a random place after attacking, and executes a new attack.
 * He uses his pistol to create 5 target marks. Eventually, he uses his pistol to shoot towards the marks.
 * Throws a icy smoke cloud, which shoots icy shurikens as it travels.
 * Throws a circle saw 3 times, which travel in a sound wave formation one after another.
 * Attempts to ground pound the player 3 times depending on where they were last standing on, creating a small icy shockwave. The third ground pound summons a swarm of icy fireballs that fall down or a bigger shockwave that moves in both directions horizontally.
 * Uses his pistol to shoot multiple bullets that move in an arc, the number of bullets increase with each shot.

When low on health, his attacks become more intense:


 * The icy smoke cloud moves much quicker and shoots more icy shurikens.
 * He uses his pistol much quicker, and the bullets move much faster.
 * He throws two circle saws three times, and they move much faster.
 * He uses his pistol to create 5 target marks twice in a diagonal state. Eventually, he shoots with his pistol quickly to those marks.

Trivia

 * His real name is Oscar Loneshot.