YOU SAID:

I have never seen anything like this.

INTO JAPANESE

私はこのようなものを見たことがないです。

BACK INTO ENGLISH

Not that I saw something like this.

INTO JAPANESE

このような何かを見たことはないです。

BACK INTO ENGLISH

Something like this is never seen.

INTO JAPANESE

このようなものを見たことです。

BACK INTO ENGLISH

It is never seen something like this.

INTO JAPANESE

それは決してこのようなものを見た。

BACK INTO ENGLISH

It has never seen something like this.

INTO JAPANESE

それは決してこのような何かを見ています。

BACK INTO ENGLISH

It has never seen something like this.