Jumping Jacks, also known as Leapers (in the in-game files) are round-specific enemies appearing in Die Rise. The first time they appear is within rounds five to seven, and appear every four to five rounds after. They spawn randomly, and can teleport in short proximity around the environment. They can be killed relatively easily, but can pick off a player that strays off on their own with ease. Two Jumping Jacks spawn per alive player at any one time. The Jumping Jack round essentially serves as Die Rise's Hellhound round, dropping a Max Ammo power-up at the end of the waves. If, during a Jumping Jack round, all of them are killed without any shots missing (in other words 100% accuracy), the last one will drop a Random Perk Bottle along with a Max Ammo power-up. This is most easily done with melee weapons or the Trample Steam only, as firing no shots guarantees that none will miss. Claymores can be placed down too, as they blow up on their target no matter what, and thus not be able to miss.
Jumping Jacks seem to be a smaller variation of the Crawler Zombies from Call of Duty: Black Ops. They are surrounded by a number of circles of electricity, and can teleport short distances on the map. They are killed in one hit with the Bowie Knife until the third Jumping Jack round and with the Galvaknuckles until the fourth Jumping Jack round, similar to Hellhounds.
They will explode in a flash of electricity which can hurt the player if they are too close to it, but is rarely lethal. They will follow a player up elevator shafts by teleporting, so there is no reliable way to evade them. They will not teleport behind the player while the player is killing other Jumping Jacks, however, they will teleport directly in front of the player and begin attacking. They are also shown to be able to jump off of walls to attack the player in a relentless and unpredictable manner. If all Jumping Jacks are killed with 100% accuracy by shooting at them and having every bullet hit them, a Random Perk Bottle will be given. If using the Ray Gun, which does not fire normal bullets, contact does not need to be made with the Jumping Jack to receive the Random Perk Bottle. Player(s) do not have to knife them all. Claymores and grenades can also be used if trying to obtain a free perk, as they do not count towards accuracy.