The Invasive Species trophy / achievement in God of War Ragnarok is unlocked once you complete all Crater Hunts in The Crater region of Vanaheim. These consist of two Epic Hunts and seven Dragon Hunts, each of which are triggered when you enter the specific area mentioned on the guide pages linked below.

Invasive Species

Complete all of the Crater Hunts

All Epic Hunts¶

• In Plain Sight
• Nocturnal Predator

All Dragon Hunts¶

• What Lies Below
• Trail of the Dead
• Path of Destruction
• For Vanaheim!
• In the Dead of Night
• Quaking Hollow
• The Burning Skies