Intrusion Coins are items given once players have maxed out any level with the Fever System, thus meaning a maximum of three coins per day. These coins allow players to intrude themselves in any Zombie Mode match past their last joinable waves (17 on Easy and 25 in Normal and Hard respectively). Players can jump in at any time during that period, even in the middle of the boss fight (both Normal and Hard difficulty), thus possible to end the round with 0 points and just collect boss tokens on a succesful boss defeat.
A nifty gimmick allows players to refill health points of every teammate upon spawning. Although it works in the last few waves, it won't work before the wave limit (as the item isn't used to join). It renders revival tokens useless as one can join at any time and heal everyone present in the game.
This item is currently available in CF China, Europe, North America, Japan, Indonesia, Philippines, Vietnam and Brazil.
- This icon was present in certain versions for as long as the mode itself was introduced, even before along with revival tokens. It is possible that it's what they had in mind back then and finally decided to implement it.
- In all CF version, it was mistakenly stated that the health refill effect does not work during Boss battle. This is untrue, the perks work in all rounds.
- CF Vietnam is the only version to offer Intrusion Coins outside Fever System - it's available in prize list for AI Tickets 3 which players can collect randomly.
- Intrusion Coins cannot be used to finish Daily Missions quicker by joining at late rounds, as the score result will not be kept. Rounds played are still logged, however.
- It's not recommended to use Intrusion Coin to join at Round 31, because players will start with only 2 lives, and they cannot collect any points aside from boss Tokens if they manage to win the round.
- Boss Arena is the only map that players can jump in at any round without Intrusion Coin (Normal / Easy difficulty). Only in Hard difficulty is where you need Intrusion Coin to join at round 7.
- Intrusion Coin also works for Defense Mode, but only when players jump in at the last round (Both Easy and Normal difficulty).