Phoenix, those stripey slugs may well be the leopard slugs ... (Limax maximus) (literally, "great slug"), also known as the great grey slug this is one of the largest kinds of keeled air-breathing land slug in the world. A beautiful slug that actually eats small slugs and their eggs. as this species is not regarded as a plant pest.
The preferred diet of the leopard slug is fungi, dead plant or animal matter making it a useful species to have around. Easily recognisable with its leopard-like spots, the species can grow up to 16cm and is commonly found in parkland, woodland and gardens.
Take a look at the pic below. They are my absolute favourite slugs in my garden.