Obtain all other Undertale trophies.
Reach the mouse hole in the Ruins.
Get to the Spaghetti save point in Snowdin.
Reach the place where it rains.
Donate 2G to the Dog Shrine.
Donate 6G to the Dog Shrine.
Donate 12G to the Dog Shrine.
Donate 20G to the Dog Shrine.
Donate 30G to the Dog Shrine.
Donate 43G to the Dog Shrine.
Donate 59G to the Dog Shrine.
Donate 78G to the Dog Shrine.
Donate 100G to the Dog Shrine.
Donate 125G to the Dog Shrine.
Donate 155G to the Dog Shrine.
Donate 190G to the Dog Shrine.
Donate 230G to the Dog Shrine.
Donate 280G to the Dog Shrine.
Donate 350G to the Dog Shrine.