Who was the last Habsburg king of Spain?

Charles II of Spain, 'The Bewitched", (Carlos II, nicknamed “El Hechizado”) (November 6, 1661, Madrid - November 1, 1700, Madrid), was King of Spain from 1665 to 1700 and the last monarch of the Spanish Habsburg dynasty.

Charles was the youngest and only survivor of the three sons of Philip IV of Spain's and his second wife -and niece-, Mariana of Austria, making Charles their great-nephew and first-cousin respectively. The king’s grandmother was also his aunt. 9 out of the 11 marriages during the 184 years the Habsburgs ruled Spain from 1516 to 1700 were incestuous.

Charles II’s tongue was so huge he could barely speak. He was illiterate and probably suffered from two genetic disorders: a combined pituitary hormone deficiency and a distal renal tubular acidosis, a condition marked by blood in the urine, weak muscles and an abnormally large head compared to the rest of the body. His autopsy revealed he had only one atrophied testicle and also he was hydrocephalic. In the absence of genetic material, these remain speculation. Regardless of the cause, Charles suffered from ill-health throughout his life, as well as depression.

He married twice. His two wives, Marie Louise of Orleans (his second niece) and Marie-Anne of Neubourg were childless.

Charles II of Spain died without an heir in 1700 at the age of 39. In his will, he chose Louis XIV's grandson, Philippe d'Anjou, as the heir to the Spanish throne. The Habsburgs’ reign was over.