Jellyfish Dress

A Dress reminding the shapes of a Jellyfish.
Once attuned and the user fully submerged, they become incorporeal within the water and grants the following:

• Attack rolls have disadvantage to hit you.
• You have resistance to non-magical damage.
• You have a swimming speed of 60ft.
• As a Bonus Action, you can make a tentacle attack, dealing 1d8 + [STR or DEX] piercing damage. On a hit, the hit creature must roll a CON Save DC 18, or be paralyzed for a minute.
  However, the wearer is vulnerable to Lightning damage at all times while they're attuned to the item.

We got this item after defeating Shime in session 44 - Drugs, Love & Party Hard.