To find this mob in-game, use BACKSPACE to open the World Search window, then enter Gosster Hantes in the Search field and click "Search". Remember, the field is case-sensitive and must be entered exactly as shown.
NOTE: After you show him your "unusual find" you receive the 14 mil. XP BUT you do not level up until you do something, anything, normal to earn XP.
I never realized what a overabundance of riches that 14mil XP quest is. Now I cannot hunt mobs that will give me XP because my gear and weapon are not high enough. I missed all the quests in between 32 and 49, and I have no clue where to start questing now. So I have gone to the other 2 classes to level up normally.
If you do this eaaster egg quest, make sure you switch to the class that you find hardest to level up.
--from a conversation on Discord