Satyr

Satyrs were creatures which resembled humans with goat legs, pointed ears, and horns on their heads. They were notoriously stupid and only interested in sex. They were the servants of Hades. (PROSE: Deadly Reunion)

Extraterrestrial life forms which resembled satyrs included Dæmons and Vegans. (TV: The Dæmons, The Monster of Peladon) A satyr-like child of an unknown species was captured and brought to the Edifice. (AUDIO: The Forever Trap) Satyrs were native to Antimasque. (PROSE: The Book of the Still)

The cybernetic stewards of the Crystal Bucephalus resembled silver and gold satyrs with diamond-encrusted horns. (PROSE: The Crystal Bucephalus)

Behind the scenes

 * According to The Brilliant Book 2012, a book that contains non-narrative based information, in River Song's World Satyrs were a pest in London, alongside Cyclops and unicorns.