Note: I am sorry for not adding this to the Bosses page. For some strange reason I cannot edit it, or at least the Editor takes forever to load. Edit
Sivv is a very tough boss in terms of attack, but with low health-it takes forty STARTING Isaac shots to kill him. He can be found in Necropolis, Utero, and Dark Room (as a mini-boss). His main attack is firing a blood beam out of his gash that will ricochet at random angles into two smaller beams, and both of those will ricochet into sets of three big blood shots in a row. He can also fire a three, then four, then five spread shot towards you from the Embryo in his head, like Krampus. At 66% health, the Embryo in his head will whistle and a Spitter will also appear in the head socket, so Sivv will now be constantly shooting single blood shots at you. At 33% health, the ricochet beam will ricochet a 4th time, each of the rows of three blood shots will ricochet into two streams of red Creep, and he can summon Chubbers, Vis, Tvisters, and Double Vis. When he dies, an Embryo, Spitter, and a Mama Guts will spawn.
Champion Versions Edit
Red: His blood beam will ricochet a fourth time right from the start, his chest cut will be red like regular Vis, and a Mama Guts will already be in the room. He will leave a trail of creep when he moves.
White: His blood beam and the ricochets of the beam and the 3,4,5 shot will all be white, and his called Spitter at 66% health will fire white IPECAC shots, and every single beam, ricochet beam, and ricochet row of shots will leave a trail of Creep underneath it, and the final ricochet trail of Creep at 33% will be thicker, but Sivv has less HP.