As long as Feraligatr is your Active Pokémon, any damage done by an opponent's attack is reduced by 10 (before applying Weakness and Resistance).

If your opponent has 5 or more cards in his or her hand, your opponent discards a number of cards until your opponent has 4 cards left in his or her hand.

You may do 50 damage plus 30 more damage. If you do, Feraligatr does 30 damage to itself.