Superterestrial or Superterrestrial: How To spell?
The word Superterestrial is misspelled against Superterrestrial, an adjective meaning "Being above the earth, or above what belongs to the earth."
Superterrestrial has double "rr" is mispronounced as "r"Remember double 'RR' in between the strings superte & estrial which should not be misspelled with single 'R'
Wrong Spelling:  superte-r-estrial  Correct Spelling:  superte-rr-estrial 
Check more misspelled words of Superterrestrial to spell it correct.