A boy coming from a million years ago

Amasso returned a boy's fossil to a human form with magical power. He sent him to the museum where the mammoth fossils, he once had as good friend, is enshrined. The boy shoots fire arrows and the mammoth fossil becomes a Haniwa phantom mammo who starts a rampage. People panic and run away. Hiroshi is hesitant to fight against the boy who is not originally an enemy.