Hello,
as the title suggests, Magic Bounce bounces back moves incorrectly.

Example:
if a grass type pokemon uses Spore on a Magic Bounce Pokemon, the move gets ''bounced back'' and the grass pokemon falls asleep which is something that shouldn't happen as this Showdown replay shows.

http://replay.pokemonshowdown.com/ou-571436472

Situation:
Breloom vs Espeon with Magic Bounce.

Breloom goes for Spore, Spore gets bounced back, Breloom falls asleep.

I didn't test it with other moves/effects, so I'm not sure if you can paralyze an electric type pokemon using the same trick.
The same could work for the move Toxic as well.

Hoping this was helpful and if more informations are needed I'm here to answer all your questions.

Thanks,

~ Xasah