"Decades-centuries, really-of research and experimentation, and I nearly had it cracked!"
"Turns out there's a magic spell for it."
Derpy clearly didn't catch that centuries bit...which is probably a good thing.
Guess their relationship has a positive charge.
He's quite passionate about his field.
"And I still need to get my suit tailored!"
Aaaannnddd he's completely forgotten Derpy came to him for help.
"What's this word you keep using..."
"...man?" (Evidently he's unfamiliar with Equestria Girls)
A relic from one of his previous looks.
Good friends...perhaps more?
"Allons-y!" (Ironically it did start out as a cavalry command.)
That's no way to treat a former companion.