I need ideas

for things that might happen to anyone attempting to study magic without proper protection....

Bonus if it's eerie and subtle
Double bonus if it's funny

Would also like to hear you stories from you on the matter.

And don't say:
>you become a wizard
!

>Magic is evil
Their souls get eaten and die
>Magic is chaos
They explode
>Magic is a flow
They become shit wizards. (Like people who learn to be programmers themselves)

They accidentally curse someone to be a shield against misfortune instead of shielded against misfortune.

You curse him to be a paladin?

>without proper protection
Crabs
Not that he gets infected with crabs, but that everything within the immediate area gets turned into crabs

......everything?!

EVERYTHING!
Even the children. Especially the children.
Everything is crab

Is this what's left of my setting now!?!?

He tries to summon a succubus and instead ends up becoming a succubus, because he didn't know that demons need a physical host.