The Speartongue is a beast/toad-type enemy from Final Fantasy XII found in the Zertinan Caverns and around the entrances to the cavern in the Ogir-Yensa Sandsea. The ones in this area are weaker and can be defeated easily, but the ones inside the cave are stronger and should be avoided at the first visit to the Sandsea.
Being a land-dwelling toad, lacking the webbed digits of its waterborne kin. Found most often in arid climes, their skin secretes an oil, thereby to prevent loss of moisture. Their hind quarters are well-suited to traveling on land, and they rear up on them when threatened, freeing their powerful forelimbs for attack.
There's a trick to getting your hands on some of the salve known as frog oil. See, the oil runs through the body along with the blood, and when it reaches the head-horns, only the oil is secreted from the tips. So that's where you need to look. However, should you kill the creature, blood and oil will congeal, making the oil impossible to extract. That's why, if you need a lot of oil, you have to cut the horns off while the creature is still alive. I didn't say it was easy.