I require some assistance, to reassure me that I am not going mad as much as anything.

I'm absolutely positive I once saw a flag which consisted of a light blue background with a big turtle in the middle of it. Not positive about the colours but am sure about a fairly large green turtle smack in the middle of it. I was sure it was the flag of the Cayman Islands.

I was quite disappointed when I went hunting for this flag earlier and could find no trace of it.

Could anyone confirm whether this flag does exist, or whether I just had some weird sort of dream where I distinctly remember the national flag of the Cayman Islands consisting of a huge turtle.

In the meantime, enjoy the Mozambique flag. It has an AK47 and a scythe, what's not to like.
http://upload.wikimedia.org/wikipedia/commons/d/d0/Flag_of_Mozambique.svg