He held a hand to the stallion, “The name's Curtis Dupree, everyone calls me Curt. What about you?”
He looked at the human and then to Twilight, giving the mare a sly grin, “Corporal Dust... Lightning Dust.”
Twilight stopped and turned to the pony causing the others to stop as well, “Dusty? What are you doing on sentry duty?”
“I asked for this post.”
“I thought you hated that armor. You always said the enhancements made you queasy.” Twilight recalled.
“After RD told me about what happened to you on the way to Apocrita, I had to hear more.”
Curt had to ask, “How you guys know each other? He an old boyfriend?”
“No, 'he' is a mare,” Twilight explained, “The armor is enchanted with an illusion that makes everypony look the same.”
“Whoa, awesome,” Curt's eyes widened as an idea struck him, “Dude, let me try the helmet on! I want to see if it works on me!”
Twilight rolled her eyes, “It won't. It uses pony magic to... wait, it uses pony magic which is the same as human magic. Dusty, take it off and let's see if it works. If anypony says anything I'll tell them I demanded it for research.”
“Okay,” Lightning Dust took off the metal cover, and tossed it to Curt, her mane and the fur on her head shifted to her natural colors.
Curt studied it for a bit, trying to feel out the spell used. Not being able to get it, he put the headgear on and turned toward the two mares. Twilight and Lightning gaped at him for a good twenty seconds before busting out laughing.
“How do I look? What the hell? Is that really my voice?” his altered voice bring further mirth from the ponies, “I need a mirror! I got to see this.”
Twilight's horn flashed, and a full body image appeared beside her. Curt mimicked the ladies' reaction at the sight of him with a pony head, gaping and then laughing. Every time he started to get himself under control, he looked up at the image and lost it. It took the trio five minutes before they could get themselves under control enough to speak.
“Leave it on for the rest of the day,” Twilight requested, “I'll say it's a psychology experiment.
https://www.fimfiction.net/story/66766/38/into-the-black-a-mares-tale/chapter-37-starswirls-legacy