How do you spell this word that sounds like mor-ma-don? I looked for it in a dictionary and can not find it?

I heard the word used several times on the radio, and in the manner it was used it described a person that foolishly believes every thing from a particular person or group without question, kind of like a useful idiot does'How do you spell this word that sounds like mor-ma-don? I looked for it in a dictionary and can not find it?
myrmidon

1.Classical Mythology. one of the warlike people of ancient Thessaly who accompanied Achilles to the Trojan War.

2.a person who executes without question or scruple a master's commands.How do you spell this word that sounds like mor-ma-don? I looked for it in a dictionary and can not find it?
Yep, like here: