Yes eating too much butter overtime can make you fat.
Butter is high in cholesterol as well as being high in calories and fat content.
So when you consume too much butter and consume those calories and fat content in excess you can have an increase in weight.
So you can get fat from eating too much butter.
Too much butter is also bad for your heart health and could lead to heart disease, heart attacks, strokes and blood clots.
Eating butter in moderation is okay but having too much butter can be and is bad for your health.