I was battling and my Mewtwo used Substitute, my friend's Mewtwo used Shadow ball on it. the Sub died and I attacked then my friend's mewtwo used shadow ball again and it sirvived it with like 25% of HP. How much damage can a Sub take?
substitutes have 25% of the HP of the pokemon that made it (rounded down), and the defenses of the pokemon they are blocking (so if you batonpass a vaporeon's substitute to a shuckle, it could last a very long time indeed.)