Some Octopuses use Coconuts as Instant Shelters.

Around 2009, octopuses were discovered suctioning coconut-shell halves to their under-sides, and then reassembling them to disappear inside. This is both a predator and prey technique as it can be used for deception or self-protection. Scientists were baffled by this unprecedented and quite frankly hilarious phenomenon. 

It makes the veined octopus the first member of the tool-making animal club without a spine. Although an octopus without shells can flee much faster, it has nowhere to flee to. Thus, the shell provides more protection. 

After the octopus is done using the coconut shells, it arranges them neatly below the centers of its body and walk around them- to quote researchers- “awkwardly.” It should also be noted, that awkwardness is also a behaviour never before seen in octopuses. 

(Source)