You can't not use Pokebank. In the original games (Red, Blue, Yellow, Green) Self-Destruct was TM 36. To get a Self-Destruct Snorlax in Alola, you would need to have one of the Virtual Console versions of the original games, catch a Snorlax, get TM 36, teach the Snorlax Self-Destruct, get Pokebank, transfer the Snorlax, and breed it in Alola. Also, when transferring from the original games the Pokemon do not have genders, so you would need to prepare a compatible Pokemon in Alola for the chance of getting a male or female.
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