Such triggers do not have validation time
Sure, you have to own the banned card, but who wouldnt want to be able to snag a Leovold, Emissary of Trest, from outside the game
Target opponent discards a card
There are only a handful of ways to remove specific cards from your opponents deck, most of which are known by the slang term capping or surgical-ing. These come from Jester's Cap and Surgical Extraction, though there are a few other cards that are similar
Its basically Negate, so it doesnt deal with problematic creatures, but its certainly a counterspell counter that you can count on
Steadily increasing in price over the years, these cards are undeniably iconic, especially the Power Nine