help with summoning and banish spell

 My idea is when you "shot" your spell the bullet spawn a mob and with the banish spell the idea is you "shot" the bullet against the mob and he is teleport looks easy isn't it but i don't what the player banish any thing like you go fight with wither and you shot the banish spell and wither be banished to another dimension so i whan spawn the mob with a tag for when i use the banish spell only summoned mobs can be banish summing up it's possible summon a mob with a tag?

probably sorry my english