The reason I doubt it's a snail or slug is because I put it up on a brick wall that's about 5' tall for about a couple hours.
While I do have other plants nearby, they show no signs of slug or snail damage.
I think it's a bird, because it did partial damage. The reason the wound is open like that is because I pulled away the dangling parts of the leaves at the site of damage.
I also doubt it's a leafhopper, they don't chew from what I understand, they pierce and suck the juices out of the leaves.
The suggestion of grasshoppers or locusts is quite possible. The rain may have disturbed it too much to do complete damage, idk.
However, like I mentioned, what ate it doesn't matter so much to me.
I'd much rather focus on what I can do from now on.
Thanks for the response, Stefano!