What will happen if you are given the wrong blood type? Will it be life threatening?

If you receive the wrong blood type during a blood transfusion the body will try to get rid of the difernet blood by sending an antibody, causing the red blood cells to clump together blocking blood vessels, and therefore causing the blood and everything in it to stop flowing and not be able to get to the brain or major organs. The blood cells then get destroyed by the body, causing yellow pigmentation (jaundice). This could be life threatening.