Slug in my cat\'s water dish?

I was cleaning out my cat's water dish when I noticed a really small slug inside it. My cat's dish is one of those kind that refills itself and the slug was inside of it, and I'm terrified of slugs so I just set that part outside and I hope it will crawl out of it somehow. Anyway, the slug was dark tan with lighter tan lines on it. Is there a way for me to identify if it's one of those creepy, dangerous slugs that can get inside of my cat and harm her or a normal slug? :/

Where are you located?
There are internet websites that will tell you the types of slugs in different areas, but I am sure it was harmless.