If I use Raichu's "Evoshock" Ability to paralyze my opponent's Active Pokemon, does the Paralyzed status condition get removed if my opponent attaches a Stealthy Hood to that Pokemon on their next turn?
The Evoshock Ability's effect is to Paralyze the opponent's Pokemon; once that Special Condition has been placed it is no longer considered an effect of the Ability at the time your opponent attaches the Stealthy Hood. Therefore, your opponent's Pokemon remains Paralyzed.
EvoshockStealthy Hood