To Take a Magmasaur egg you must have a Maewing to do this steps:

Step 1:found the magmasaur cave

Step 2: enter with maewing

Step 3:be fast,fly high, take the egg and go away

Step 4:take some sulfur

Step 5:put 6 fireplaces and the magma egg in the center

And that is! You have a magmasaur!