Convergence to function that is not measurable
Pick a non-measurable subset $E$ of a null set, and let $f_n=0$ for all $n$. Then $f_n\to\chi_E$ a.e.
Pick a non-measurable subset $E$ of a null set, and let $f_n=0$ for all $n$. Then $f_n\to\chi_E$ a.e.