Most nebulas are very big some of them being hundreds of light years in length and others are not very big they can be of all shapes and colours and not one of them looks the same as another, even thought they clump together and become bigger they are very light for example a nebula the size of the earth would only be a couple kilograms in weight. |
Also if you have a big imagination you will find that nebulas can actually look like things here on earth for example people, animals, nature, insects etc.