It looks awesome! Something for higher mana battles, which my water deck is missing. Only other taunt i think is Kraken, but he's very expensive. I think Wave Brood would go well as a back-line tank to protect Oshannus from melee/ranged attacks, paired with Kelya to nullify a physical attack, or with Bortus to tank alot magic attacks seems amazing.
I would love to have one!