octopus
蛸 centers on the octopus, a sea creature known for its eight arms and soft body.
蛸 combines the insect radical 虫 with 肖, which likely contributes the sound. The character is used specifically for octopus, though the historical reason for the insect radical is uncertain.
The insect radical 虫 suggests a small creature, and the right side 肖 looks a bit like a rounded body with dangling arms. Picture an octopus clinging to a rock with its eight limbs.
For ソウ, imagine an octopus sewing its arms together: sew -> ソウ, and the octopus becomes a tangled knot.
octopus
common octopus (Octopus vulgaris)
seven-arm octopus (Haliphron atlanticus)
long-armed octopus (Octopus minor)
giant Pacific octopus (Enteroctopus dofleini); North Pacific giant octopus
algae octopus (Abdopus aculeatus)
winged argonaut (species of paper nautilus, Argonauta hians)
Japanese sea biscuit (Clypeaster japonicus)
Penthorum chinense (species of saxifrage)
octopus; man with a bald or shaven head
man with a bald or shaven head
octopus pot
long, thin-bladed knife used for sashimi preparation
spotted jelly (Mastigias papua); lagoon jelly; golden medusa; Papuan jellyfish
boreopacific armhook squid (Gonatopsis borealis)
eggcase (shell) of the winged argonaut
many-legged; octopus-like
bogus dividend
greater argonaut (species of paper nautilus, Argonauta argo)
flapjack octopus (Opisthoteuthis depressa); pancake devilfish