Insta Kill Rounds

Insta Kill Rounds are a bug in zombies that happens in a high round when zombies get so much health that they will reset back to the health of round 1 zombies, which is 150 damage.

On World at War, insta kill rounds on Nacht and Verruckt start at 163, but on Shi No Numa and Der Riese they start at a later round. For every dog round you get, the insta kill rounds get delayed by one round. They will start somewhere about round 208. This is not the case for Black Ops 1.

On Black Ops 1, Insta Kill Rounds start at 163 and are then every other round until 185 and then it becomes a bit random. The known insta kill rounds for Black Ops 1 are 163, 165, 167, 169, 171, 173, 175, 177, 179, 181, 183, 185, 188, 189, 191, 194, 196, 197, 199, 202, 204, 205, 207, 210, 211, 214, 216, 217, 219, 222, 224, 225, 228, 229, 231, 234, 236, 237, and 239.

On Black Ops 2, Insta Kill Rounds start somewhere between round 223-255. Black Ops 2 has "true" Insta Kill Rounds, meaning that the zombies will die from literally anything, including running them through the fire on Tranzit.