Complex sentence: The older Baby Pokémon have a different defense: if a Baby Pokémon is attacked, the attacker must flip a coin; if it lands tails, the attacker's turn ends without an attack.
Split into simpler sentences: The older baby pokémon have a different defence, if a Baby Pokémon is attacked, the attacker must flip a coin. If it lands tails, the attacker's turn ends without an attack.