Slugs - yuck

There are loads of huge gross orange slugs around and the odd one that is much bigger (15 cm) and kind of mottled.
The other evening it rained around dusk and they came out in even greater numbers than usual on to the lawn. We put out a beer trap to see if we could catch them. They could obviously sense it and flocked towards it enthusiastically. Disappointing in the morning there were only 3 actually trapped.