someone's bad idea of her

[Maybo]

Sybil is a cat. Yesterday, the cat chased off an animal and came back today. The owner found it look different and sent a photos of it to her husband who was on a business trip. I'd like to know what "someone's bad idea of her" mean?

Excerpt from the book:

“Eric,” she whispered. “I don’t think that’s Sybil.”
“Don’t be silly,” I said, internalizing a scoff. “Of course it is.”
“No. She feels different. Her fur is too coarse. I don’t like to touch her.”
“Maybe she’s just dirty,” I offered. “She did just spend the night in the woods.”
“And she sounds weird. You heard her. She sounds off.”
I paused, thinking. “I don’t know, babe. Do you want to take her to the vet?”
She released a sigh of frustration. “No.”
“Why not?”
“Because it’s not her.”
“Amy,” I chided. “It’s not,” she insisted in a loud whisper. “It’s like… someone’s bad idea of her.”
I was beginning to get irritated. “I don’t know what to tell you,” I said. “She looks fine to me.”

Source: At Home With the Horrors: 14 Tales by Sammy Scott

 

[Skrej]

It's not her cat, but a poor copy of her cat created by someone who didn't know the original cat very well.

 

[teechar]

It's not her cat, but a poor copy of her cat created by someone ______ didn't know the original cat very well.

I don't know whether it's necessary in AmE, but I would put "who" in that blank.

 

[Skrej]

Oops, I was a victim of my own editing! Fixed.