Typical Tentacle Tactics

All giant octopuses in videogames fight the same way. They will face you in the center of a circular arena, use two of the Combat Tentacles to restrict you to a small portion of the arena, whip with other tentacles, and have a spit projectile (often some kind of blinding ink). Needs not be an octopus, but does need to be similar.

Tentacle Rope is often involved.

Action Adventure

 * The Legend of Zelda Spirit Tracks, The Ocean Temple boss.
 * As well, in all Zelda games, there are plant bosses, fought shortly after gaining the boomerang, or less commonly inside a giant fish. They use tentacles, whip at you, trip you, use the tentacles to smash the ground, and on occasion spit. Naturally, you need to cut them down and stab them in the eye.
 * There is a monster in Onimusha who burrows his tentacle-arms and grapples with them.
 * Averted in Kao The Kangaroo Round 2, where the octopus boss doesn't try to restrict your movement; instead, you avoid its tentacles as you swim around the arena, trying to shoot all the tentacles and expose its weak point.
 * Legacy of Kain: The Elder god.

Action Game

 * Devil May Cry 4: Echidna.

First Person Shooter

 * The first form of Emperor Ing in Metroid Prime 2 does the standard whipping attacks, but can also stab Samus through portals.

Platformer

 * Several bosses from the Sonic Adventure games fight like this.
 * Big Squiddy in The Legendary Starfy attacks this way, but the only projectile is the occasional boulder.
 * King Kaliente in Super Mario Galaxy acts a bit like this, at least the centre of the arena, projectile spit and dangerous tentacles part.
 * There's a cephalopod boss named Gooper Blooper in Super Mario Sunshine who attacks like this.
 * Averted in Ecco the Dolphin. The octopus is sitting on a rock ledge and just sits there slapping its tentacle to impede your passage through the tunnel.

Real Time Strategy

 * The Forgotten One boss in Frozen Throne attacks by spawning tentacles from the ground. Since they have melee range, they end up next your units, so you end up literally Surrounded By Tentacles while the boss spits fire at you.

Role Playing Game

 * Phantasy Star Zero, the marsh boss.
 * The Tentacle bosses in Final Fantasy VI aren't quite this trope as its described, but at the same time the battlefield is your characters standing on the tentacles as well as fighting them.
 * Ultros, on the other hand, does have an Ink attack but otherwise averts the trope.
 * Dragon Age: Origins: the Brood Mother.
 * King Kalamari in Super Mario RPG: Legend of the Seven Stars averts this in a variety of ways. First, you progress toward its head, fighting two waves of three tentacles and then the head and the two remaining tentacles. It only needs one tentacle to restrict control of a party member, tossing them into the air for a few turns, then dumping them back on you with a Weakness ailment. It does have an ink spit but that's also a common enemy attack in the game.
 * Octomammoth from Final Fantasy IV actually loses tentacles as it takes damage.
 * Averted in Kingdom Hearts. You'd think Ursula, who does occasionally use Typical Tentacle Tactics in The Little Mermaid, would use them here; but you only fight her when she's giant size so you just swim around keyblading her in the face.
 * Played straight in Re:Chain of Memories, where she uses her tentacles to smack you around the stage before coming close enough that you can attack her face.
 * The Kraken boss in Fable.
 * The Kayran in The Witcher 2: Assassins of Kings is a fairly straight example of this kind of boss. Its immobility is justified by the fact that it's under a paralyzing spell that allows you to fight it in the first place, and its inability to retreat makes it extra mad. Unusually it keeps its tentacles out of reach for most of the time, forcing you to use a magic sign to temporarily trap them to the ground as it strikes you in order to do any damage. It also spits sticky poison and throws rocks.

Survival Horror

 * Though not a squid, Ramon Salazar, after his "ritual" from Resident Evil 4 certainly pulls this off. And be careful with those tentacle arms; one of the attacks is a One Hit Kill.
 * The final boss of Dead Space plays this trope pretty straight, including the "forming an arena by cutting off all escape routes with my tentacles."