I can find none that start with the letter P.
Orc
The two that immediately come to mind are the Loch Ness Monster and the Leviathan.
What is the name of a Mexican dish starting with the letter T?
A musical instrument starting with the letter g is a guitar.
I can find none that start with the letter P.
Azog, a goblin monster.
Azog was king of the orcs in Khazad-dum (Moria). He murdered Thror.
One example of a Tolkien monster with three letters in its name is Orc. Orcs are a common creature in Middle-earth, often depicted as fierce and ruthless warriors serving dark powers like Sauron.
First of all, his name is J.R.R. Tolkien. John Ronald Reuel Tolkien. His moms name was Mabel Tolkien. His dads name was Arthur Reuel Tolkien. =)
Arthur Tolkien's birth name is Arthur Reuel Tolkien.
Christopher Tolkien's birth name is Christopher Reuel Tolkien.
John Tolkien's birth name is John Francis Reuel Tolkien.
Michael Tolkien's birth name is Michael Hilary Reuel Tolkien.
Priscilla Tolkien's birth name is Priscilla Anne Reuel Tolkien.
Octopus
J.R.R. Tolkien's father's name was Arthur Reuel Tolkien.