Like all other Pokemon games, Yellow offers a few one-shot opportunities to catch Pokemon that the player can see in the overworld. With the exception of one of these Pokemon, it is the expectation that the player catches them the first time he or she encounters them - running away or defeating them will cause them to disappear forever, should the player forget to save before the battle.

#143 Snorlax

Location: Route 12, Route 16

Method:
The incredibly lazy Normal-type Snorlax appears in two places in Yellow; the first is on Route 12 east of Vermilion City. The second appears west of Celadon City on Route 16. Both block the way to the paths to Fuschia City so at least one must be fought in order to proceed. It is recommended that you purchase Great Balls before the battle as Yellow has an annoying "the ball missed the Pokemon!" message that can appear with weaker balls.

Snorlax
Level 30
OT:Yours
ID:Yours
Amnesia
Headbutt
Rest