Medical question about a problem with my vision.?

Sometimes, randomly, I can see like this odd shape in my eye. It's kind of like in a tentacle shape and it's filled in with what looks like static from t.v. It's only in my left eye in the bottom or top corner. It's really weird and it's happened quite a few times already. I can't see anything where that shape is placed and it makes it hard sometimes to concentrate. It lasts for about 30 mins-to an hour. I don't know if I should see a doctor because obviously this is kind of hard to explain (and not to mention REALLY weird) and it doesn't seem like anythings wrong. I'm just worried that it might progress to the rest of my eye or lead up to something else? Am I just seeing things? Or is this normal? Has this happened to anyone else?