Very strange episode of parts taking over and acting out

Hi, sorry, new here. I am not sure how much energy I have to explain my experiences up to this point but today I had an experience of about 15 or so minutes long where my parts were each taking over and talking to me. It started with verbal compulsions in a voice that sounded young and then eventually my youngest part took over: pulling angry faces, sticking my head out and saying things. But there was a lot of my eyes switching and head making random movements and pausing still and not being able to do anything. I don't usually switch like this and my parts usually only communicate internally. It was weird, they barely had anything to say. Multiple parts tried speaking but it was really a lot of jerking around and me being like 'guys, wtf is going on?'

They told me they wanted me to experience what it feels like for ME to be out of control and not the one making all the decisions. I got freaked out and wanted them to stop but for the whole time its like I really couldn't stop myself if I wanted, and they wanted me to know what that felt like, them taking over.

What does this mean if this is starting? I lived most of my adult life with near total dissociative amnesia. Ive been reprocessing the trauma for a few years now, experienced some psychotic stuff - eventually led into discovering parts through IFS, and then on. Its only since last summer I realised I was a 'system'. Its just getting super weird for me.