It is impossible.
to get Blissey you need to first catch a Chancey in the safari zone it takes awhile for most people but have patience then when you catch Chancey train it for awhile nd make Chancey like you more and then eventually it'll evolve into a Blissey
in some cave
what you do is go the place where a girl says she will trade areodactyl for a chancey and search that patch of grass but it has to be daytime.
You find Chancey in the Meadow Zone of the Safari Zone. You can also catch one on Routes 13, 14, and 15.
Find it north of Solaceon town or evolve a Happiny
Just be patient and find one in the safari zone,the only place they are
you find it on the route right of fuchsia city,but they are very rare fuchsia city is in kanto.
chancey evolves into a blissey
Chancey's population is 148.
Blake Chancey was born in 1962.
Chancey Juday was born in 1871.
Chancey Juday died in 1944.