Otherwise known as Senecio herreianus, the String of Watermelon has trailing branches that are covered with striped, watermelon shaped beads. More sun creates strong striations and less sun creates a more lush green look. As a trailing variety, you should allow the String of Watermelon to spill over the edge of planters - they are fast growers and drape or hang quickly.
These will want a little more frequent watering than your other succulents but it's always best to let the soil dry out completely between waterings.
Sold in a 3.5" Nursery Pot.