In Dota 1, both Lone Druid and spirit bear could carry and cast necronomicon (the spirit bear could only do so if it had mana from a point booster or energy booster, as in Dota 2). However, in Dota 2, an additional set of necronomicon creeps can be summoned without destroying the first two. This is not possible in Dota 1. I don't know if this is intended, but I think it may be related to a bug that was posted here: If the spirit bear creates any summoned units in Dota 2, they are unaffected by Lone Druid's Battle Cry.