The infallible word of God, in the form of the koran states that genies (spirits with free will) exist.
"The Djinn are said to be creatures with free will, made from 'smokeless fire' by Allah in the same way humans were made of earth."
According to the koran (infallible word of God) Muhammad wasn't only sent as a prophet of mankind, but also these Djinn (Genies).
From Wikipedia:
Jinns: Similar to humanity, jinns have free will allowing them to follow any religion they choose to, such as Islam, Christianity, Judaism, Hinduism, etc. The only difference is that they are made of smokeless fire and therefore are not visible to humans. There are more jinns than humans, in terms of population. Jinns have the power to fly and fit in to any space so they live in remote areas, mountains, seas, trees, and in the air, in their own communities. Similar to the humans, Jinns will also be judged on The Day of Judgement and will be sent to Jannat (heaven) or Jahannam (hell) according to the life they lead.
Fitting into "any space" is a physical impossibility.
Do the religious folk here, REALLY believe they exist (or their existence is feasible)? Let me just point something out: it is a FACT that there does not exist an entity with free will and intelligence made from 'smokeless fire'.