Putting A4 paper in a regular toaster is a dangerous and potentially hazardous action. It should never be attempted as it can lead to serious consequences, including fire and damage to the toaster.
A4 paper is not designed to be heated in the same way as food items, and it is flammable. When exposed to high temperatures in a toaster, the paper can catch fire and produce flames, smoke, and toxic fumes. This can not only harm the toaster but also create a risk of spreading the fire to nearby objects or causing injury to anyone nearby.
Toasters are designed to safely heat food items and have specific temperature and timing settings suited for that purpose. They are not intended for non-food items like paper.
In summary, putting A4 paper in a regular toaster is a fire hazard and should never be attempted under any circumstances. Always use toasters and other appliances according to their intended purpose and follow safety guidelines to avoid accidents and injuries.