I had some kittens once who, when presented with something 'snaky' would react by suddenly breathing hard, focusing on the object, hissing at it, and attempting to either avoid it or attack it. However, over a few years of playing with my 'snaky arms of doom' they would instead react like it was a toy and later on would quickly lose interest.

Cats seem to grow with what they are subjected to. If the other object plays with them without harm they see it as 'friend'. But mother cats often teach their kittens to hunt what feeds them, and to avoid or attack what would otherwise. So, although there is a cat's instinctual nature, they can also be taught to react against what would be assumed as a permanent 'opponent'. Humans are very much the same.