Ayya Vaikundar (Tamil: அய்யா வைகுண்டர்), according to Akilattirattu Ammanai (or Akilam), a scripture of the Ayyavazhi, was a Manu (father, sovereign) Avatar of Narayana, incarnated as Muthukutty or Mudisoodum Perumal, a Nadar of Swamithoppe, Tamil Nadu (c. 1810 — c. 1851). He is referred to as Sampooranathevan, a deva (a deity).

The exact date of birth of Mudisoodum Perumal is unknown. It is mostly placed in either 1810 or 1809, while others follow the view of Akilam.

In 1809 a child was born to the couple Ponnu Nadar and Veiyelal in south India, at Swamithoppe in the Kanyakumari District(part of Travancore then). They were very poor. They initially named the child Mudisoodum Perumal, meaning "Lord Vishnu with a crown", but due to objections from those of higher castes, the family changed his name to Muthukutty.

The religious book, Akilam, tells of a legend of a child who was born dead, and then the soul of the deva Sampooranathevan was placed in the body. According to the legend, the parents found the child still for a time immediately after birth, then the child began behave normally. Thereafter, that boy grew up called Muthukutty in human history, and Sampooranathevan in Ayyavazhi mythology.