Wave Contract (波契約; nami-keiyaku) is a family introduced in BS66, possessed exclusively by the Contract card, Petit Shack, and the Azure Wave family cards with Contract Advent that support Petit Shack.
As Petit Shack is The PartnerShark Shack's form after losing most of his power on Judgment Day, it adopts a new contract name that reads tamer than Azure Contract (蒼契約). The name is probably taken from the Azure Wave (蒼波) family, like the relationship between Petit Lampo's new family and Jade Thunder. It also matches with the image of Petit Shacks' deck: attacking the opposing deck at multiple instances, waves after waves.
Cards in the family are either Contract Advent forms of Petit Shack himself, or Spirits that Petit Shack got affiliated with while he was recovering under the sea, or on his journey traveling around Lecoulis following Toa and the others.
