A token copy of Pacifism is an Aura enchantment token named Pacifism with mana cost {1}{W} and the abilities enchant creature and “Enchanted creature can’t attack or block.”

The token enters the battlefield at the same time as Domesticated Mammoth. If it can’t legally be attached, it will be removed as a state-based action afterwards.

For effects that look for or modify the creation of tokens, the token copy of Pacifism is considered to have been “created” and those effects will apply. For example, Doubling Season will really calm that Mammoth down.