Extra-defined senses in a human.
You heard me blink? Dude, you have spidey senses.
The sensation that a spider is crawling on you when it is not. This usually comes directly after finding a spider on you and can last for days after.
Sam: Betty, is there a spider on me?!
Betty: No, dude, it's just your spidey senses.
Sam: Yeah, I've been this way ever since I found a spider on me when I was in the bath the other day.