Castles In the Sea / Get Your Coat

S1 E16: While playing in the sand on the beach, Duck and Shark discover the perfect home for Shark: a sand castle! But why, oh why, does it disappear every night while Shark is sleeping? When the WordFriends try to hunt down the castle thief, they learn about tides and waves' from a singing Crab. Duck thinks Frog doesn't want to play in the rain because Duck accidentally broke Frog's boat. But the real reason is that Frog doesn't like the rain. Duck learns all about words that end with "oat" before finally coming across a word that will allow Frog to play outside in the rain: a coat!