Regardless it caught my eye. At first I thought burnnnnttt! Im new... It's a error or it isn't? Teach me don't clown me please.
It don't look like toning to me. It looks like somebody took a marking pen and made a small mess on it.
It's toned. The coin came in contact with the environment and it turned a gold color, very common. Gold toning on clad coins happens a lot. So in your own words, it's pretty.