Watermelon Begonia is just one of many names given to Peperomia Argyreia, just look at those beautifully patterned leaves and striking red stalks, it's not hard to work out where the name comes from.
With the right care these lovely little plants will grow to around 6-8 inches. They are non-toxic to cats and dogs, so no need to worry with curious pets around.
It likes bright shade, direct sun will scald leaves, you could try pairing with a taller plant that can provide the shade it needs. You know when it's getting too much light as the colour in the leaves will fade.
Water carefully, as they like to dry out in between waterings, but too dry and the leaves will start to wilt and fall. Wait until the top of the soil feels dry to the touch and then give it a generous watering. Water much less in winter months.
Really easy to propagate (propagation is the process of creating new plants from a cutting, an offset or a seed. I'm going to do a whole blog post about this soon!).
Trim a leaf at the bottom of the stem, place in a cup of water, wait until it grows roots or dip the bottom of the stem in rooting solution and repot straight away.