Boss Events

Boss Events are weekly BTD6 events where you fight one Boss Bloon through five tiers on a set map. Each tier is tougher than the last, and you win by destroying the tier 5 boss before round 140 starts. Every event has a Normal and an Elite version, an optional ranked leaderboard, and solid rewards just for clearing the tiers. They are also where Paragons shine, since bosses were added to the game alongside them.

How Boss Events work

A Boss Event usually starts on Saturday at 02:00 UTC and ends on Thursday at 03:00 UTC. The featured boss rotates in a fixed order: Bloonarius, Lych, Vortex, Dreadbloon, Phayze, Blastapopoulos and Diamondback. When an update adds a new boss, it gets the spotlight for four weeks before the normal rotation continues. While a boss is featured in the event, you cannot pick it in the regular Boss Challenge mode.

Tiers and boss rounds

• The tier 1 boss appears on round 40.
• Each following tier arrives 20 rounds later: 60, 80, 100 and finally tier 5 on round 120.
• If a boss reaches the exit, or is not beaten within 20 rounds of spawning, you lose, even if you have lives left.
• While a boss is on screen there are no breaks between rounds, even with auto start turned off.
• You win as soon as the tier 5 boss dies. If round 140 begins first, you lose.

Each boss has skulls on its health bar. Reaching a skull triggers that boss's special ability, which is usually the dangerous part of the fight.

Normal vs Elite

Elite is the hard version of the same boss on the same map. Elite bosses have far more health, stronger abilities and often different tower restrictions or leaderboard type. You start with 200 lives on Normal and 100 on Elite, and in single player you must beat tier 5 of the Normal boss before Elite unlocks.

Default rules

Most Boss Events use Medium difficulty, Standard mode and $650 starting cash, though Easy, Hard, CHIMPS, Half Cash, Alternate Bloons Rounds, Impoppable and Reverse have all appeared. You can place up to four Paragons. Many weeks restrict the tower list or the heroes, and Vortex weeks usually speed up bloons. Fast Track is allowed outside ranked mode and starts you on round 35 with $10,150.

Checkpoints

Boss Events do not use normal continues. The game saves a checkpoint every 20 rounds (20, 40, 60, 80, 100 and 120). Going back to a checkpoint costs Monkey Money, starting at 100 and rising by 100 for each later checkpoint. If you lose, you can also retry the last round for twice the checkpoint price. Simply closing the game and returning restarts the current round for free.

The Boss Bloons

Each boss has its own page in our Pedia with full mechanics and counters. In one line each:

• Bloonarius: slow and very tanky, spews bloons as it takes damage and dumps huge bloon clusters at each skull.
• Lych: heals over time, steals temporary buffs from nearby towers, summons tombs that spawn blimps, and turns untouchable at each skull until its souls are popped. It also cuts the sell value of your towers.
• Vortex: extremely fast, speeds up other bloons, destroys projectiles with storm pulses and stuns nearby towers at each skull before retreating.
• Dreadbloon: has Lead properties and reduces all damage by 1, and is immune to one tower category at a time (Primary, then Military, Magic and Support at each skull). Its Dreadrock bloons taunt your towers.
• Phayze: a Camo boss with a speed-boosting shield, warps forward at each skull and regularly jams Camo detection buffs such as Radar Scanner for 12 seconds.
• Blastapopoulos: has Purple properties, shrinks tower range, heats up when hit (especially by fire, plasma and lasers) and stuns everything when it overheats. Ice attacks cool it down.
• Diamondback: a long segmented boss whose head blocks pierce, with a shielded rattle tail. Breaking the tail shield stuns it and makes it take double damage for a while.

Ranked mode and leaderboards

Before starting, you can tick the Ranked box to compete on a leaderboard. Ranked mode disables Insta Monkeys, Powers, Double Cash, Fast Track and other paid boosts. Each week Normal and Elite each use one of three scoring types, and lower is always better:

• Fastest Time: a timer runs only while the boss is on screen, across all five tiers.
• Least Cash: counts every dollar spent on towers, upgrades, obstacle removal and similar purchases.
• Least Tiers: counts every tower placed and every upgrade bought, including hero levels.

All three also track time as a tiebreaker. There is a hidden penalty timer for slow non-boss rounds: if bloons are still on screen a short while after the last one of a round has spawned, that extra time is added to your boss time at the end. Income abilities also pause their cooldowns while this penalty timer is running, even outside ranked mode.

Ranked can be played in Co-op as well, with separate leaderboards for teams of two, three and four. On top of the global ranking, you are placed in a Mini-Boss leaderboard of up to 100 players with its own prizes.

Rewards

Every tier you beat gives rewards, and you collect them once per event:

• Tiers 1 and 2: 50 Monkey Money each on Normal, 100 on Elite.
• Tier 3: 75 Monkey Money and a Power on Normal; 150 Monkey Money, 5 Trophies and a Power on Elite.
• Tier 4: 100 Monkey Money, 5 Trophies, a Power and a Tier 2 Insta on Normal; 200 Monkey Money, 15 Trophies, a Power and a Tier 3 Insta on Elite.
• Tier 5: 125 Monkey Money, 25 Trophies and a Tier 3 Insta on Normal; 250 Monkey Money, 50 Trophies and a Tier 4 Insta on Elite.

Ranked placements pay extra, from 50 Monkey Money for the top 75% up to 1,000 Monkey Money, Trophies, a Power and a random Tier 5 Insta for first place. In total, clearing both Normal and Elite every week is one of the best weekly sources of Monkey Money, Trophies and Insta Monkeys.

Co-op Boss Events

You can fight the boss with up to three other players. The boss gains 20% health for each extra player (+20% with two, +40% with three, +60% with four). Each player gets the full tier rewards, but only if they have not already earned them solo. Unlike regular Co-op, there is no extra starting cash.

How to beat Boss Events

Farm early, especially on Elite

The single most important tip is income. Normal bosses can sometimes be beaten with a pure defense, but Elite bosses are practically impossible without farming. Start Banana Farms early when they are allowed. Benjamin and Geraldo are the most common heroes because both speed up early farming.

Split your defense

You need two things at once: heavy single-target damage for the boss and enough general defense to handle the regular rounds. The boss rounds keep coming without breaks, so a weak crowd-control setup will leak while your damage focuses on the boss.

Learn the boss abilities

Every boss punishes a different habit. Do not rely on buff towers against Lych, bring Camo detection that does not depend on Radar Scanner against Phayze, spread your tower categories against Dreadbloon, and avoid stacking only fire and plasma against Blastapopoulos. Read the boss page before you start.

Plan for Paragons

With up to four Paragons allowed, a Paragon is often the cleanest answer to tiers 4 and 5. Build toward one while your farms pay off.

Boss Rush

Boss Rush is a separate team event that alternates weekly with Contested Territory. A team clears five islands, each with a random map and boss. In each battle the boss fully heals and gains more health every time you pop it, while the next round starts at once. Your score grows with every pop, and the battle ends when the boss reaches the exit or you run out of lives after using your two revives. Team members pool their best scores to defeat each island's target, and the team's tower roster shrinks while it gains relics as islands fall. Players use tickets to enter battles, and you can pick any hero except Geraldo. Full rules, rewards and tips are on our Boss Rush page.

Boss guides on this site

Find our current boss strategies in the Boss Event guides and Boss Rush guides. For a full walkthrough, see our videos on the BTD6 Master YouTube channel.

Frequently asked questions

What round does the boss spawn in BTD6 Boss Events?

The tier 1 boss spawns on round 40, and each new tier arrives 20 rounds later, ending with tier 5 on round 120.

How do you unlock Elite boss?

In single player, beat tier 5 of the Normal boss in the current event. Elite then unlocks on the same map.

How many Paragons can you have in a Boss Event?

The usual limit is four Paragons.

What happens if you do not beat the boss in time?

If a boss survives 20 rounds after spawning, or reaches the exit, you lose. You can return to the last checkpoint for Monkey Money.

What is the best hero for Boss Events?

Benjamin and Geraldo are the most used because they help early income. When they are banned, pick a hero with strong early damage or useful buffs.

Do Insta Monkeys work in Boss Events?

Yes in normal mode, but Ranked mode disables Insta Monkeys, Powers, Double Cash and Fast Track.