Green’s Dictionary of Slang

transmogrify v.

also transmigrify, transmography
[subseq. SE, OED suggests orig. version was transmigrafy and links it to illiterate corruption of SE transmigure or transmigrate, to move from one place to another]

to metamorphose, to alter.

[UK]‘Basilius Musophilus’ Don Zara Del Fogoy vi (1719) 33: So that he remained for a time as one trans-elemented. [Note] Meaning transmografide, or metarmorphosed into a Mandrake [OED].
[UK]T. Shadwell Squire of Alsatia III i: I know I am Transmography’d: But I am your very Brother, Ned.
[UK]B.E. Dict. Canting Crew n.p.: Transmogrify to alter, or new vamp.
Fielding Love in Several Masques V iv: I begin to think myself [...] that some wicked Enchanters have transmographied my Dulcinea.
[UK]Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
J. Jortin Ecclesiastical Hist. i 254: Augustine seems to have had a small doubt whether Apuleius was really transmogrified into an ass [F&H].
[UK]Foote A Trip to Calais in Works (1799) II 329: You’ll find the names of things plaguily transmogrified all along this coast.
[UK]Grose Classical Dict. of the Vulgar Tongue n.p.: Transmography, or Transmigrify, to patch up vamp, or alter.
[UK]Lex. Balatronicum [as cit. 1785].
[UK]Egan Grose’s Classical Dict. of the Vulgar Tongue.
[UK]M. Scott Tom Cringle’s Log (1862) 73: Jonathan [...] let drive his whole broadside: and fearfully did it transmogrify us.
[US]‘Jonathan Slick’ High Life in N.Y. I 214: Sometimes they transmogrify what I write till I shouldn’t know it was mine.
[UK]Hotten Dict. of Modern Sl. etc.
[UK]Hotten Sl. Dict.
[UK]P. M’Neill Blawearie 84: We [...] made our way here and are quite transmogrified to find everything so outrageously transformed.
[UK]G.F. Northall Warwickshire Word-Book 249: Transmogrify. To transform.

In derivatives