Per patch 1.100 (12.15.09):
* Gjalpinulva has been increased in difficulty and will now have a chance to spawn more frequently. Additionally Gjalpinulvaâ€™s corpse will now decay within a half hour in order to allow players to forcibly spawn him once every half hour if Gerrikâ€™s Sword is used.
* Adolescent dragons have been increased in difficulty.
Per the 1.101 Release Notes 02.24.10:
Gjalpinulva: The damage values of this monster have been reduced. The main breath weapon attack now gives an immunity timer that protects against further resistance debuffs. The primary special attacks have had their reuse timer increased from 2 minutes to 5 minutes. New mechanics have been put into place to target inattentive players.