Magmasaur egg stealing: On Fjordur, head to the volcano with an Andrewsarchus. Beware Fire Wyverns and X Rock Elementals. Search for some magmasaur nests and grab the egg. Then run as fast as you can. There is some sulfur you can feed the baby magmasaur so it doesnt die. It smells metal and cooks raw meat. I don't know how to hatch it other then an incubator.

Hope this helps, Best luck to those who try.