I've thought of another one!
False Security: The Pokemon with this ability is immune to all status effects, but it tries to make it's opponents believe it's not immune.
For example: When it get's burned it's Attack doesn't get lowered and it won't take damage from the burn, but it'll still say that it's burned. When it gets paralyzed it's Speed doesn't drop and it'll never get fully paralyzed, but it'll still say that it's paralyzed. When the Pokemon get's confused every turn it'll say "[Name] is confused!" but it will never hit itself in confusion. When the Pokemon falls asleep, it'll always wake up on the same turn (or the next turn if it moved last).