The bonus Vishgraz receives due to its last ability may cause it to survive combat damage in some cases. For example, if an attacking Vishgraz is blocked by a 3/3 and another creature with toxic 1 is attacking at the same time and is unblocked, Vishgraz with deal 3 damage, receive 3 damage, and get +1/+1 at exactly the same time. The end result is that it will stay alive and be a 4/4 creature with 3 damage marked on it.