Tide Spirit
Drops from Docile Frosty Soul. I wish that I could bind the tides and bend them to my will. But in its depths the sea abides and waits for no one still. Elemental type.
The 
Tide Spirit is a battle pet obtained as a drop from capturing and opening a 
Frosty Soul in the Azure Span during the Dragonflight expansion.
Guide awaiting review
Craft Required Capture Tools
To capture a Frosty Soul, you will need an 
Empty Soul Cage and a 
Zapthrottle Soul Inhaler — both are crafted professions items. The Zapthrottle Soul Inhaler must be channeled while the elemental dies, so using damage-over-time abilities and stuns to prevent interrupts is the recommended approach. You can also move while channeling the Zapthrottle Soul Inhaler.
Farm Awakened Revenants at Imbu
Head to Imbu in Azure Span to farm Awakened Revenants for Frosty Souls. At 60.44, 65.94 there are NPCs that will attack nearby mobs — pull an Awakened Revenant to them and let the NPCs assist while you channel your capture. A second cluster of helpful NPCs can be found at 56.59, 64.52, where you should clear the non-elite mobs and adds at the bottom of the hill near the water before pulling the Awakened Revenant up to the NPCs. A third group of NPCs is located at 56.23, 64.89 and works similarly.
Target Earthshatter Elemental
Another location to farm for Frosty Souls is the Earthshatter Elemental at 52.8, 30.6 in Azure Span.
Wait for Docile Soul Timer
After successfully capturing a soul using the Empty Soul Cage, do not open the 
Encaged Frosty Soul immediately — wait for the 15-minute timer to expire and for the status to change from "Encaged" to "Docile" before opening it. The resulting 
Docile Frosty Soul has a chance to contain the Tide Spirit pet, though it will more commonly contain the elemental crafting reagent.
Check the Auction House
If you prefer not to farm, the Tide Spirit is tradeable and may be available for purchase from other players on the Auction House. One player reported obtaining the Tide Spirit in only 3 attempts, suggesting the drop rate may be more forgiving than other Spirit pets.
Tips
Interrupt an Awakened Revenant's cast, then immediately activate the Zapthrottle Soul Inhaler — this timing window makes it easier to complete the capture before the mob dies.
