The magmasaur will be Arks equivalent of long ranged artillery, being able to fire powerful blasts at long distances, but it is also effective at close range, having a Velonasaur stile AOE attack and doing damage to anything withing range just by existing. It is not however effective everywhere all the time, depending on biome, weather and temperature changes how strong its attack is, how much stamina and material is used and so on. In high temperatures and dry areas it does most, while cold and wet areas it does least. Lastly for convenience purposes it is also a portable forge and can swim in lava. Note:The magmasaur does damage to friendlies near it as well, only one who is safe is whoever is in the saddle, so this creature will need to be kept alone away from the base or in a separate pen.
Magmasaur is able to destroy ALL STRUCTURES utilizing its searing spit. While it is a walking forge it produces metal at the same rate as a refining forge. You can use the jump button to taunt other creatures and when holding searing spit use crouch to erupt. (This attack pushes creatures back and leaves magma everywhere) it is breedable in lava. Hope this helped