Hi I was hoping if anyone knew any great scenes from anime,cartoon or even live action of costumes taking over their wearing anf changing their personaility?

The Symbiote (though it's a being and not solely a suit)
Not Hypno-related, but there's a game called Costume Quest where you transform into a creature based on your Halloween costume. It had a cartoon on Amazon Prime.

I believe this was the theme of the new konasuba game on steam.

I confirm! Basically there are clothes that alter the personality of the wearer to make them act the total opposite way: Darkness becomes a dom instead of a sub for example. Each of the main girl will get affected and in addition to that, you have to craft a hypnotic clothe during each arc and oyu can "test it" on any of the girl.

In addition to that Konosuba game, there is a martin mystery ep where people eat cookies made by a possessed woman and if they eat it they act like their Halloween costume.

Examples of what happened: Martin acted like a baby because he accidentally received a baby costume.

3 kids acted like ghouls

their mom laughed because she had a clown costume.

the ep can be found here (I can also translate anything they say) www.youtube.com/watch?v=AZzRhoTpsYk