General terms:
* Octopod: Refers specifically to octopuses, which are eight-legged cephalopods.
* Arachnid: A broad term for creatures with eight legs, including spiders, scorpions, ticks, and mites.
* Multi-legged: A more general term for creatures with many legs.
More specific terms:
* Araneae: The scientific order for spiders, which are all eight-legged.
* Scorpionida: The scientific order for scorpions, which are also eight-legged.
* Acari: The scientific order for ticks and mites, which are also eight-legged.
Descriptive phrases:
* Having eight legs
* Eight limbs
* With eight appendages
The best word or phrase to use will depend on the specific context and the level of detail you want to convey.