In the quest to discover what “There can be only one” means, I tried sacrificing all fifth tier towers at once, sad to say I don't think anything happened. Based on the
Bloons TD 6 Community Race `B.A.D. v2` in 1:38 by tobi439
The best heroes in Bloons TD 6 - Gamepur
There can only be one. | Bloons TD 6 Amino
There Can Be Only One (Monkey Knowledge Point) | Bloons Wiki | Fandom
Magic Knowledge There Can Only Be One - KnowledgeWalls
Magic Knowledge There Can Only Be One - KnowledgeWalls
There Can Be Only One (Monkey Knowledge Point) | Bloons Wiki | Fandom