Is cereal bad ? does it make you fat?

Unsweetened cereal isn't horrid, but almost all of it is processed so it's not "healthy" per se. If you consume more calories than your body uses, then you'll gain fat. There is no single food type that will "make you fat". You get fat when you eat more than your body can use, so it stores the excess (instead of just eliminating it).

Yeah, calories from cereal can be stored as fat.

Technically yes. Most of them are high in unnatural carbs and sugars. Plus combined with milk, cereal tends to fill you up for only a short period of time and yet adds quite some fat to your waistline.

Depends on the type. Several things fall into cereal. If you eat fiber one cereal, then it is meh. It is highly processed and our bodies don't exactly absorb the sprayed on minerals and vitamins very well. Now on the other hand, steel cut oats are healthy. They are not highly processed and nothing is added because of that.

Fatness is achieved by overeating not just the type of food. Eat reasonable portions, avoid snacking and eat only healthy food.

Depends on the cereal. Read the label.

The sugar in it does.