"아잉 몰라잉" and "아잉, 난 몰라잉". The normal form is "아이, 몰라" and "아이, 난 몰라", where 아이 is an exclamation of embarrassment or disappointment. (난) 몰라 means "I don't know" literally, but it's actually more like "I don't know what to do" or "I'm at a loss". The extra "ㅇ" makes it sound childish sounding, suggesting the speaker can't seem to think for themselves. In real life, no one says it like this (except maybe some 3 year-olds) because it sounds too stupid and even offensive. But cartoons go to extremes of employing all kinds of such unrealistic gimmicks in an attempt to make it interesting.