Tentacool is card #80 of 102 in HS—Triumphant (2010), a Common illustrated by Sachiko Adachi. At about $7.05 it is the #65 most valuable card in the set. In a HS—Triumphant booster it turns up about once every 5 packs. It is one of 16 Tentacool cards printed so far.
1999Fossil
2002Legendary Collection
2003Aquapolis
2006Legend Maker
2010HS—Triumphant
2017Guardians Rising
2019Unbroken Bonds
2023151

















See the full HS—Triumphant card list
An ungraded Tentacool from HS—Triumphant sells for about $7.05. A PSA 10 is worth more, roughly $56.40 by our estimate, and a PSA 9 around $19.74.
It is a Common, and it shows up about once every 5 HS—Triumphant packs.
Sachiko Adachi drew the art for this card.
Yes, as a digital simulator. Holobrook lets you open HS—Triumphant booster packs in your browser with the set's real pull rates and keep what you pull in a digital binder. No real cards, nothing to buy.