1966 British sci-fi/horror flick starring Creator/PeterCushing, set on a small island which is besieged by "Silicates," bizarre critters with tentacles that kill their victims by sucking their skeletons out. Cushing plays pathologist Brian Stanley, who along with hunky colleague David West and West's girlfriend Toni Merrill, travels to remote Petrie's Island to investigate said monsters, which were accidentally created by reclusive cancer researcher Dr. Phillips. The things reproduce via mitosis and will soon overrun the island, forcing Stanley and West, with help from local doctor Reginald Landers, to race against time to find a means of destroying them.

Not related to ''TerrorIsland''.
!!Tropes used in this film:
* AnAxeToGrind
* AnyoneCanDie: [[spoiler:Dr. Landers, a main character for the first half of the film (to the point where he's almost a DecoyProtagonist), dies at about the middle mark. Stanley himself ''almost'' falls prey to this trope, but some quick thinking on West's part ([[AxCrazy and an ax]]) saves 'im.]]
* ApocalypticLog: Dr. Phillips' notes.
* BodyHorror: All those boneless corpses.
* ChekhovsClassroom: The seemingly innocuous conversation Phillips and his assistant have at the beginning.
** Ditto Phillips' notes, which mention both the missing Great Dane and the fact it got an accidental dose of Strontium-90. The scene of the main characters discussing all of this is very brief, however, so if you don't pay attention you're liable to wonder about the significance of the dead dog Dunley finds. Fortunately, Stanley is there to remind us.
* ChekhovsGun: The axe in the mansion. It's glimpsed a few times before Landers uses it in a failed attempt to kill a Silicate.
** ChekhovsBoomerang: After Stanley leaves the axe by the front door, it's forgotten about [[spoiler:until West needs to use it to cut off Stanley's hand to save him.]]
* ChekhovMIA: The missing dog alluded to in Phillips' notes. Also doubles as ChekhovsClassroom since it's only mentioned when West and Stanley are going over the notes.
* ClosedCircle: Not only are they on an island, but a boat only comes ''once a week'' and the helicopter that flew them there has to leave early on.
* CombatTentacles
* CuriosityKilledTheCast: Several characters just ''have'' to go and see what that weird noise is.
* DangerousWindows
* DarknessEqualsDeath: Which is why GenreSavvy Stanley turns the lights on!
* DeadpanSnarker: Stanley.
* DirtyCoward: Halsey.
* TheEndOrIsIt: [[spoiler:The ending scene involving the Japanese scientist.]]
* {{Foreshadowing}}: The opening scene has Phillips' assistant Carson asking if they should wait for the teams in other countries to coordinate their experiments.
** It's mentioned [[LampshadeHanging early and often]] how the island is pretty much cut off from the rest of the world.
** Also the faulty generator and the flickering lights it causes.
* ForScience
* GenreSavvy: The characters (at least the main characters) go out of their way to avoid many dangerous situations, almost never split up when they can help it, and when they first entire the dark and scary mansion, one of the first things they do is turn on all the lights instead of continuing to wander around in the dark.
* GettingCrapPastTheRadar: Before the takeoff, our three leads have this... odd discussion:
-->'''Stanley''': What the devil did Napoleon do on that island of his to keep himself busy?\\
'''West''': He invented solitaire.\\
'''Toni''': [''playful''] I have a much better game in mind.\\
'''Stanley''': [[AThreesomeIsHot Can three play]]?\\
[''West smirks and shakes his head'']\\
'''Stanley''': [''resigned''] [[ADateWithRosiePalms Fascinating game, solitaire]].
** Also:
-->'''West''': [[TheLoinsSleepTonight I may not get places as fast as a Maserati]].\\
'''Toni''': But you do get there eventually.\\
'''West''': Eventually.\\
'''Toni''': When?\\
'''West''': I'll let you know.\\
[''they kiss and the doorbell rings, interrupting them'']\\
'''Toni''': [''slyly''] [[PrematureEjaculation Is that a pit stop or the checkered flag]]?
* GoneHorriblyWrong: [[spoiler:The scientists were looking for a cure for cancer.]]
* ImmuneToBullets: And dynamite. And {{Molotov cocktail}}s. And axes. And... pretty much anything really.
* IslandOfMystery: The Silicates' island.
* HellIsThatNoise: The Silicates' weird electronic warbling.
* HorrorHunger
* LifeOrLimbDecision: See AnyoneCanDie above.
* TheLoad: Toni.
* MadScientist: Averted. Dr. Phillips is a perfectly well-intentioned, albeit careless, scientist working for the betterment of humanity.
* TheMainCharactersDoEverything: West and Stanley more or less take over towards the end, doing all the important stuff, while the ostensible actual head of the island, Campbell, is relegated to a supporting role.
* MyCarHatesMe: Your typical "engine stalls during a monster attack" scenario.
* OfficerOHara: Constable Harris has some traits of this. It's okay, though, since the movie ''is'' set in Ireland, after all.
* OurMonstersAreWeird: The Silicates.
* PhlebotinumMuncher
* PickyPeopleEater
* ReasonableAuthorityFigure: Island "boss" Roger Campbell.
* ScienceMarchesOn: West's speech at the end of the film basically boils down to this.
* SiliconBasedLife: The Silicates.
* WhatHappenedToTheMouse: Where did Dunley disappear to during the climax?
* TheXOfY