Monkey Bombs (also referred to as Cymbal Monkey in Black Ops 3) are a great secondary tactical grenade option to have, specifically in the fan-favorite Kino der Toten map.
Their unique attribute of luring the zombies away from players and towards themselves and then subsequently killing them all in an explosion makes them a must-have to reach higher rounds.
What if there was a way they could be upgraded so that they detonate in less time and deal more damage? Well, there is a way to upgrade Monkey Bombs in Black Ops 3 Zombies.
How to upgrade Monkey Bombs in Kino der Toten
Do note that these instructions apply to any BO3 Zombies map except Gorod Krovi. Before starting the match, equip the Mega Gobblegum Crate Power. This will make the next weapon you get from the Mystery Box Pack-A-Punched (the upgraded enhanced versions).
Now, jump into a match of zombies in Kino Der Toten and get this Gobblegum from the Gobblegum Machine. Once equipped, head to the Mystery Box and request a weapon. Keep doing this until you get the Monkey Bomb.
If you choose any other weapon instead of the Monkey Bomb, you will essentially waste your Gobblegum and will have to equip it again from the Gobblegum Machine.
The Monkey Bomb that you now possess will be the upgraded, Pack-A-Punched version. It will have a shorter blowing time, will deal more damage, and has some cool visual and audio effects as well to add to its uniqueness.
Something important to note here is that upgraded Monkey Bombs kill till about Round 25-30 in Kino der Toten. They then start acting like ordinary Monkey Bombs.