From the comfort and authority of my armchair, as a (fake) psychologist, I declare that you can’t be a psychopath if you feel guilty about a spider (and other beings, especially humans).

I think of gaslighting as manipulation of a victim by an abusive person by causing the victim to doubt their own feelings and perceptions, thereby gaining control over them. They do this by convincing the victim that what they are feeling and observing is false and the fault of the victim rather than the abuser.

This has a better explanation and some clear examples:

newportinstitute.com/…/what_is_gaslighting_abuse/