I do go outside sometimes, I jog in the woods a few times a week, but I'm pretty sure I would've noticed a tick latching itself onto my knee. It might be a spider, but the chance is small I think since where I live we don't really have venomous spiders or spiders that leave a serious mark. I've never even heard someone say they've been bitten by a spider. I wouldn't be surprised if they wanted to go after me though, I kill every spider I come across in my house haha