Just wondering why that color on the back?

https://preview.redd.it/2l5agjsftzmf1.png?width=1483&format=png&auto=webp&s=4be810faecb87c5f1f9077faa2c803d142dfe108

The cat also looks to be injured, can't walk normally, otherwise it was overjoyed to be petted a bit.

https://preview.redd.it/fbjbco0otzmf1.png?width=1335&format=png&auto=webp&s=ead23e45c3caa705ecb17f3104f929ddd9de45fe