Standing beside a mill appears to be the remains of a woman with her head supplanted by that of a donkey. The sets of remains appear equally decayed, suggesting that the figure has been in her mannequin-like position for some time. The origin of this macabre scene, the potential identity of the woman's remains and whether or not this may have been some supernatural being all remain unknown. The reactions of the protagonists to these remains suggest, however, that this may have been a living creature.
The Donkey Lady is a reference to a glitch of the same name in Red Dead Redemption, where the game would spawn an NPC with the A.I. and face of a donkey. The glitch became popular after a Youtube channel by the name of WhereDaBootz made a video showcasing the glitch.
Considering that New Austin is locked until the epilogue chapters, it is unknown why Arthur Morgan is able to give an alternative entry in the journal.
Arthur's drawing: "What the hell was this poor thing?"
John's drawing: "What was this poor thing? Who would do such a thing to any creature"
Red Dead Redemption 2 Easter Egg 9 - The Donkey Lady
The Incredible Donkey-Lady!-0
The original Donkey Lady in Red Dead Redemption, which this point of interest is referencing.