Monkey vs. Monkey

"Sometimes, the best defense is a good offense. We can earn more City Cash by taking it from other Monkey Cities. Show them that you are not to be messed with."

- "Raid someone!" Quest description

"Don't wait around after you have been raided by someone else. If you want to get them back, you get one chance at revenge. Gather all of your Bloontonium and give them everything you've got."

- "Revenge is best served hot" goal description in BMC

"Beware! Incoming Monkey vs Monkey attacks work differently to attacking normal tiles around our city. In MvM the Bloons will not stop between rounds and each wave will follow right behind the previous wave."

- Advice from the Army Monkey in BMC Mobile when defending for the first time

 (or MvM), is a feature in Bloons Monkey City that allows players to attack other players with bloons assaults which players will have to defend their city from. The attacker will receive City Cash, XP, and Honor for successful raids, but they will lose honor for lost attacks. Players can choose not to participate by not attacking any player for 72 consecutive hours; this is called "pacifist mode". This will prevent any attacks from coming to the player. However, players who have over 1000 honor or attack someone during Pacifist Mode will be susceptible to attacks. (the latter will break out and have to wait for 72 more hours again or lose his/her honor to make it below 1000).

Attacking Players
To participate in Monkey vs Monkey, the player's city is required to be at least level 9. Also, the player needs several buildings to raid and defend against other players: When attacking a random player (a Quick Match) or a friend (Attack Friend feature), the player will have the option to choose the highest bloon type and amount of Bloontonium spent. Attackers with higher city levels will require having higher-ranked bloon types to attack, as well as a higher Bloontonium requirement. Also, the player will be given the option to send extra regrowth, camo, lead, and MOAB-Class Bloons for the price of 10 for each extra option chosen, and 15 for regrowth. The more Bloontonium the player sends, the more bloons will be generated. At the highest levels, the highest and lowest ranks will range from all MOAB-Class Bloons. However, the rounds will be computer-generated, and the defense rules for the other player will apply. In BMCM instead of assaults there are strategies and instead of being optional, you have to choose one of three random strategies which can be rerolled with 10.
 * Bloon Inflation and Deployment Facility: This is required to send an attack against other players. In BMCM, This structure has a different look, takes 2x2 tile, generates and stores its own Bloontonium, and players can only launch attacks when their Bloontonium supply is at 100%.
 * Bloontonium Storage Tank (Flash Only): This building is necessary for the player to store Bloontonium, which can then be used to assault other players.
 * Bloontonium Generator (Flash Only): This facility generates Bloontonium at the rate of a Banana Farm building. It is one of many ways to generate Bloontonium; the player also can fill their tanks by defending other players' raids, capturing MOABs Graveyard tiles, or using Bloonstones. (As a bonus, their tanks will be filled up on their first attack)
 * Bloon Research Lab: This laboratory is required to research and send bloon types stronger than green bloons.

Defending an Attack
When a player gets an attack, it's placed on the lowest difficulty tile they have (random on mobile), and often appear closest to the 3x3 section of city where they started. Some tile types however, such as of mountain or volcano terrains, are less readily targeted. The player has to defend the tile in apopalypse-style; if they lose, money and honor is stolen from their city and if the player doesn't have enough cash for it, random buildings are temporarily disabled (always one is disabled on mobile even if the player has the money) which can often be frustrating. Also, there is a 24-hour time limit which starts after a player logs in after an attack is sent. If the time limit expires before the player defends their city against the attack, then they automatically lose just as they would if they lost all their lives, but in the battle history, the track picture is replaced by a 'Attack Expired' picture on a stopwatch with a monkey pointing to it. If this occurs, defenders won't get salvaged bloontonium because they didn't defend their city in the first place.

Differences between Flash and Mobile
Mobile:
 * Exclusive in-game music is absent (uses tile music)
 * No bloonstone cost to retry defense upon loss. However, your opponent will receive more rewards upon doing so.
 * Can pause in-game
 * Attacked tiles are random
 * Tiles are not captured regardless of battle outcome, no bloonstones or city cash is given for beating the attack either (just honor and bloontonium).
 * Bloon Inflation Factory takes 2x2 tiles; generates and stores Bloontonium, replacing storage tanks and generators; can only attack when 100% full
 * A Building is required for each: Fast Bloons, Thermal Bloons and Rainbow Bloons.
 * DDTs can't be sent in an attack. (However, it is possible but rare for a DDT to appear in an attack with 28 rounds.)
 * Money stolen is based on player's level, and is greatly reduced (to 75 x PlayerLevel). However, this is replaced with a building always being destroyed, even if the player has enough money.
 * Honor award amounts are fixed. Losses are -2 honor for losing, regardless of city level, difficulty of attack, or your opponent's honor (succeeding defended attack is always +10, succeeding an outgoing attack is +15, defending attack on first try is +2 honor, second and beyond is +5 honor and some cash).
 * Attack Types/strategies and are used instead of Assaults, and have an option to send extra strong attacks (for the price of 10, free during Warmonger).
 * No matter if you have 1000 honor or more, you are still able to enter Pacifist Mode on any honor count.

Flash:
 * Honor gained/lost is based on opponent's honor, and that amount is higher than that on mobile. (30 honor on average, both for losing and gaining, and only 1 honor is gained between both players)
 * Variable Difficulties for attacks, minimum bloontonium amount is 250*OpponentLevel - 1000, and can range from Medium to Hard (below level 12), Very Hard (levels 12-32), Impoppable (level 33 and up). The maximum amount of bloontonium that can be used as part of an attack is 1.33x the minimum amount.
 * Can send multiple assaults in one attack.
 * City Cash is stolen is based on the level of monkey banks.
 * For level 1, it's 50% of its capacity (750).
 * For level 2, it's 40% of its capacity (1800).
 * For level 3, it's 33% of its capacity (2970).
 * For level 4, it's 25% of its capacity (3750).
 * For level 5 and above, it's 20% of its capacity (so 5000, then 7000, 10000, and 15000).
 * Buildings only get damaged if you don't have enough city cash.
 * Bloontonium Generators, Bloontonium Storage Tanks, and Bloon Inflation and Deployment Facilities are three different buildings that only need a single tile for each.

Trivia

 * The number of towers damaged is ambiguous when it comes to the Road Spikes or the Pineapple. The red text stands for the number of road spikes or pineapples that are unusable, while the white text stands for the total number of Road Spike or Pineapple towers, which give out road items in groups of 5.
 * Only towers that require Unit Buildings are eligible to get damaged.
 * Banana Farms will never become damaged regardless of how many other buildings damaged. This is because the Banana Farm buildings goes under the category "Resource", not "Unit".
 * Free Dart Monkeys and other free towers do not get damaged; the others are eligible to become damaged.
 * In BMC Mobile, a damaged building is represented by a generic unconstructed building that is under repair by Firefighter Monkeys. One is angry (with similar anger to the Full Metal Jacket Sniper Monkey) and washing the fire with a hose (it has number 99 on its helmet), while the other appears sad with its hands behind its back (it has number 11 on its helmet). Both have "FOMC" written on their helmets.
 * In BMC Mobile, the player is still vulnerable of attack after building a Bloon Inflation and Deployment Facility, even if they did not attack anyone.
 * In BMC flash, the MvM button has two animal paws prints on it.
 * When a MvM attack is threatening somewhere around a player's city, the tile the attack is on cannot be played in normal mode. In BMC Mobile, the attack can be played in normal mode once again once the MvM defense is done on that attacked area.
 * In BMC Flash, there are six monkey faces, depicting each difficulty. The Baby Monkey stands for the weakest attacks (down to Red Bloon attacks), the Engineer stands for somewhat weak attacks (up to about Thermal Bloon attacks), the Mortar Monkey with a cigar stands for moderate strength attacks (which at its point is strong Ceramic Bloon attacks), the Point Five Oh Sniper Monkey with a cigar stands for somewhat strong attacks (which here goes to about strong MOAB attacks or weak BFB attacks), the Robo-Monkey stands for moderately strong attacks (of about strong BFB attacks), while the TOTMG or Sun God stands for very strong attacks (the strongest of strong attacks, of ZOMG or DDT attacks).
 * It is possible to earn bloon-related goals by defending attacks containing such bloons. This includes the "Dark Dirigible Titan" goal being able to be completed if successfully defended an attack containing DDTs.
 * By default, the player is not in Pacifist Mode. This is until the player accepts with the "Do you want Pacifist Mode" message, which only arrives after clicking on the Monkey vs Monkey menu.