It was a skill crystal.
"Whoa!!!" Ace exclaimed. He was really surprised to get this thing. As he had reached level 20 for almost 2 weeks, he had killed dozens of monsters, but somehow he had never gotten even a skill crystal. It was really a rare thing.
He thought he must kill a monster with a level of more than 20 to get a skill crystal. But, it seemed it wasn't the case. The vampire that he had killed was only level 15. So, he concluded that it was not about the level of the monster, but it was more about its extremely low drop rate.
Ace then checked its description.
"Bingo, hahaha. It seems my luck is really great today," Ace said with a wide grin on his face.
[Bats Transformation]
Rarity: Very Rare