BTD Battles: when do the special arenas come like moab pit +?

Its for a game called Bloons TD Battles from steam and id like to know when do the special arenas come like Moab Pit,BFB Colosseum,Vortex,blastapopulu

Its for a game called Bloons TD Battles from steam and id like to know when do the special arenas come like Moab Pit,BFB Colosseum,Vortex,blastapopulus,bloonarious swamp you can search it on google I cant find it myself

or:Its for a game called Bloons TD Battles from steam and id like to know when do the special arenas come like Moab Pit,BFB Colosseum,Vortex,blastapopulus,bloonarious swamp you can search it on google I cant find it myself

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