What is the "strange platypus-like creature" referenced in abberant mind's origins?

Question

I don't recall any “strange platypus-like” creature in D&D, let alone one appropriate for the Aberrant Mind. I can only think of Perry the Platypus from the Phineas and Ferb cartoon. Nevertheless the Abberant Mind's origins describes such a creature:

As a child, you had an imaginary friend that looked like a flumph or a strange platypus-like creature. One day, it gifted you with psionic powers, which have ended up being not so imaginary.

The Flumph is name checked, and I'm aware of that creature. What is the other one?

Answer 1

It's most likely a reference to an unimaginatively named creature called a Thought Eater:

Thought eaters were rarely encountered creatures that existed on the Border Ethereal, the border between the Ethereal Plane and Prime Material plane.

They are described as platypus-like:

These creatures were described as resembling emaciated, sickly gray skeletal platypuses with over-sized heads. Despite being skeletal, their paws had webbing and they used them to swim throughout the Border Ethereal. However, to creatures on the Prime Material they were completely invisible. Whenever the corpse of one was encountered on the Prime Material, it was assumed to be a platypus that had died of starvation.

(Emphasis mine)

As an aid to this answer, David Coffron says:

I found no reference to platypus in any of the other popular settings' wikias I searched (including Dark Sun, Dragonlance, Eberron, Greyhawk, Planescape, Ravenloft, and Spelljammer).

So, in other settings this may not be a Thought Eater, but at least in the forgotten realms it is.

_{References from the wiki:}

• _{A Guide to the Ethereal Plane, p. 72. ISBN 0-7869-1205-7.}
• _{The Complete Psionics Handbook. (TSR, Inc.), p. 120. ISBN 1-56076-054-0.}
• _{Monster Manual, 1st edition. (TSR, Inc), p. 94. ISBN 0-9356-9600-8.}
• _{The Sword of the Dales. (TSR, Inc), pp. 11–12. ISBN 1-56076-848-7.}