It's hard to predict the exact impact of any one species extinction. When the ecosystem is disrupted enough, it will collapse and do so quite rapidly. Will the loss of the octopus trigger the collapse? You just never know. At the very least, the people who like to eat, look at, or sell octopus will be effected.
What would happen to the invorment if the octopus was extinct?
Sperm whales would have to find something else to eat.
I know nothing about the Dumbo octopus, however I know that if any animal goes extinct the food chain would somehow be disrupted, consequentially also the ecosystems home to the octopus.
Wikipedia
Definitely the blue ringed octopus! The blue ringed octopus is VERY venomous! This type of octopus can shoot it's venom through the water!
The blue-ringed octopus lives in the ocean an therefore the term 'landscape' would not apply to where it lives.
You would be likely to fing a blue ringed octopus at tidal pools, reef flats at WA marine park
Shark
It depends on the size and type of the octopus and shark. A giant octopus can kill and eat a leopard shark, but a common octopus will be a prey of a tiger shark. Blue ringed octopus have deadly venom enough to kill a full-grown whale shark.
A blue ringed octopus is typically 1-2 inches long. That would make the head... find the body proportions and then do the math.
Techincally speaking, octopi do not sting - they bite. And the one you would be thinking of is the small Blue-Ringed Octopus, found from Japan to New Zealand (but they are most commonly found in coastal regions of Southern Australia). Point of interest - all octopi have a venomous bite, but only the Blue-Ringed octopi's bite is fatal to humans.
A blue-ringed octupus kills with venom, so if it bit you, there is a chance you might die. Would it bite you if you touched it - it might well do. But it cannot poison you from skin contact alone.
It would be extinct. As in no longer in existence. It would not be here anymore.
other animals that relied on it would die and come extinct
we would all be in caves or extinct
they would be fat