From the Waves

You have learned how to harness greater power through your elemental heritage

• Increase your Constitution or Wisdom score by 1 (your choice)
• You may cast the Wall of Water  and  Control Water spell without expending a spell slot or material components as a 4th-level spell. Constitution is your spellcasting ability for these spells. Once you cast these spells, you can't do so again until you complete a long rest.

Adapted from Greater Call to the Wave by S3nat