If anyone cares, I have found a historical use of the Terrify action against the Egyptians. One that may go against our values to some degree, but would be plausible for a Heroic Mystic to think of.
Behold!
Source:
Ancient Egyptian Warfare
Behold!
Surrender or the kitten dies! said:The Persians invaded in 525 BCE and defeated the Egyptian garrison at Pelusium but this had nothing to do with superior military might. The Persian general Cambyses II knew of the great veneration the Egyptians had for animals in general and cats in particular. He ordered his men to round up as many animals as possible and drive them before the army. Further, he had his soldiers paint the image of the goddess Bastet, among the most popular of all Egyptian deities, on their shields. He then marched on the city with the animals in front of him declaring that he would hurl cats over the walls if he did not receive an immediate surrender. The Egyptians, fearing for the safety of the animals (and also their own if they should offend Bastet), lay down their arms and surrendered. Afterwards, Cambyses II is said to have thrown cats from a sack into the faces of the Egyptians in contempt.
Source:
Ancient Egyptian Warfare