This is such a hard to answer question because all of the characters have their own brand of chaos :,)
IM GONNA GIVE YOU FOUR DIFFERENT ANSWERS, ONE FOR EACH CHARACTER SET
Starting with the s1 group of characters, I'm gonna go ahead and say it's Ness & Rex
Bad ideas are had, and even more are followed through on with these two
For s2a that's a really tough one, but, I think it's gotta be any combination of Lucky, Felix, and this guy who's name I'm still working on, but who I've been lovingly been referring to as Windbreaker
There's a lot going on with these three
S2b's chaotic duo without hesitation has to be Pearl and Captain Cuttlefish
And s3's most chaotic duo is definitely these two, who also don't hsve names yet (bc I just started working on them since Splat 3 is *just* coming out and I didn't want to do much until we had more of it)
Theyre not allowed to be on the same team anymore