The reality star and mother-of-two took to her Instagram story Saturday to complain about True's latest obsession ... saying her daughter's bringing home whale books with super realistic depictions.

Kardashian says she almost feels her daughter's bringing home the controversial material just to mess with her ... before she flips the book over so she doesn't have to see the picture on the front.

And then, Khloe shared another pic ... a whale True seemingly drew. To be fair, It's a pretty comical depiction -- not at all lifelike -- but, it seems KK still can't handle it ... 'cause the real animals turn her into a blubbering mess.

Remember ... Khloe revealed her fears to her followers on X last year -- saying she knows it's totally irrational, but those monsters of the deep blue sea really freak her out.

And, she also had a very memorable freakout during the season 4 premiere of "The Kardashians" ... check out the clip, but maybe cover your ears a bit!