For the record, I had been trying to offer slugs to my pallidulus garter for some time after first getting her, and she showed no interest at all. Repeated attempts failed.
Meanwhile, the slugs were occasionally escaping from the container where I was keeping them and making looooong straight lines across the floor in random directions.
If you're interested, a big slug goes about 10 feet overnight hehehe.
Too bad there's no market for them; I could gather them by the dozens, day or night!