wierd sounds

(this was in 1.12.2)Hi i have a question i was playing minecraft today and.... lets just say some wierd sounds that i never hear playing (im playing for 7 years)(singleplayer) it was stutery and like a hacker sounds i imediantly left and started trieng to find the sounds in the files and internet but noting was it that i heard can u give me some info about this, thx