Aquarium.. kill the Seruf boss in the Shrimp monsters place and it will have a chance to drop
At Ludi
pretty much anywere in maplestory near hennnesys..... many places
internet
At Ludibrum
my bum :)
In Sleepywood dungeon
You can get them from Mushmom and Mushmom's Grave.
Henesys
You can't.
you can find octopus by kerning city. they are in the construction site
Near perion
in the woods and the dark lair