Got a new spell randomly

[LoneKnight667]

So im new to the game. I played for a bit, getting out of the tutorial cave, decided to start new character.
Started new character, decided to level a few skills to level 10, but then had to leave for a few hours. Came back, booted up the game and loaded the save. and immediately got a notice in the left corner that I learned a new spell. Snowball, destruction class spell.
I did not do anything. what happened and is this normal, or bug? Or is it Bethesda normal bug?

[CHASE6]

Sounds like you are a nord; default spell.

[LoneKnight667]

Originally posted by CHASE6:

Sounds like you are a nord; default spell.

I thought so too, except that I am an imperial. Decided to go super basic for my first run, especially since I'm doing max difficulty.
Much harder than max difficulty skyrim

[Wai]

Each magic school skill has one free spell attached to it if, and only if, your character has that skill as a major skill. So, when you changed your character you chose (or defined) one with destruction as a major skill. That is how you came by the extra spell. Race does not matter for this it is the class (or your chosen majors if using a custom class) which has this perk.

[arottweiler]

You'll receive spells as you complete quests and it's displayed in the top left corner but is easy to miss especially when it follows another notification. Sometimes the NPC will offer to teach you the spell which you can decline but most of the time it's added to your spell list automatically. In vanilla Oblivion there is no way to delete spells which isn't a problem early on but eventually you will be at a higher level and all the low level spells will be redundant so a simple mod like Spell Delete is useful for removing all the spells that are no longer required and makes it easier to manage the useful spells. Also useful if you use mods to create your own spells and end up with multiple spells while experimenting.

https://www.nexusmods.com/oblivion/mods/23069

Hotkey health potions and health spells and use the spell as much as possible. Only use the potions in an emergency so you can work on increasing your restoration skill. Some followers/bodyguards are useful at higher difficulty levels so buy as many summon spells you can cast and use the services of The Jemane Brothers. You meet them during a quest that you can do at the start of the game and they will remain with you until you complete the quest. They only have basic wait and follow commands but are two very powerful fighters and have decent AI so can follow you in to Oblivion gates. They don't have the option to access their inventory but you can do this with the Active Inventory spell and give them potions, weapons, armour, torches and summon spells which they will use. The only downside is they will use a summon spell regardless of enemy so it's wasted if they use it for a mudcrab. Give followers summon spells sparingly to avoid wasting them.

https://www.nexusmods.com/oblivion/mods/17497

[Bob of Mage]

You could have learned it from a spell book if you have the DLC that adds them. There will be an NPC mage that will make a beeline for you right at the start (he spawns really far away, but can track you) and he will always have one such book on him. SO you could have looted the snowball book and used it when you weren't paying attention.

[Wai]

Originally posted by Bob of Mage:

You could have learned it from a spell book if you have the DLC that adds them. There will be an NPC mage that will make a beeline for you right at the start (he spawns really far away, but can track you) and he will always have one such book on him. SO you could have looted the snowball book and used it when you weren't paying attention.

Except, you have to open the book. It goes unopened into the inventory when looted so, it would be rather hard to read it by accident.

The OP said he changed his character at the sewer entrance and then had to leave without further actions. Snowball would have been added because Destruction became one of his Major skills though it was not one with his original character, but, if he left immediately, the message would, very likely, not have displayed before he saved to exit.

It is true that some quests give spells, very specific to the quest (messages can easily be missed when this happens, not random (messages can easily be missed when this happens) and the spell books can be found randomly as loot, but, not at the sewer gate.