Toxic component of a type II toxin-antitoxin (TA) system. Has ssRNase activity. Its RNase activity is partially neutralized by cognate antitoxin VapB. Rapidly induces apoptosis upon microinjection into mouse fibroblasts (L929 line). Probably contributes to host cell death if bacterial cell lysis occurs during host infection. Belongs to the PINc/VapC protein family.