I would like to mention that Tentacool deserves at least D-Rank.
In fact, the only thing holding it back is its complete lack of useful recovery, as many psychic and electric special attackers have difficulty 2HKOing it without boosting, which is free set up turns.
- It is at least as viable a spinner as Wartortle, and manages to support its team with toxic spikes, and knock off.
- With max investment and an eviolite, Tentacool's special defense is godly, lending it the ability to come in on, and frustrate, many special attackers (Gorebyss, Ludicolo, Amoongus, Vileplume, Charizard, Butterfree, Haunter- to name a few).
- To note: A +3 Max SpA Ludicolo with Life Orb cannot Ohko with Giga Drain, and instead deals catastrophic damage to itself from Liquid Ooze- with stealth rocks and two layers of spikes. (I include this only because it has won me a game before, and was really funny)
In fact, the only thing holding it back is its complete lack of useful recovery, as many psychic and electric special attackers have difficulty 2HKOing it without boosting, which is free set up turns.