I think all the tenticals on Oddworld that we have seen look different to each other and move differently... And just because different creatures have tenticals it dosent mean their related to each other.
Parimite tenticals are more fingers then anything and can only open and close, in and out.
Slig tenticals on the other hand have much losser joints able to move side to side at least some extent. They also have what seems to be rigged sections on their tenticals a little like Parimites. Not a huge link though.
The members of the Octgi famly who have tenticals on the other hand do not seem to have any joints in their tenticals like Parimites and Sligs. They have tenticals in the truest sence.
So Im pretly sure that none of these creature are not related closely. But just like on Earth all cretures probly came from the same single celled bactrum or simple animal...
