If you have 3 or more "Destiny HERO" monsters in your Graveyard: You can discard this card, then target 1 "Destiny HERO" monster in your Graveyard; Special Summon it to your opponent's field in Defense Position. Negate any Spell Cards or effects you activate, and if you do, destroy that card. During your Standby Phase: You can banish this card and 1 "Destiny HERO" monster from your Graveyard; each player chooses 1 Normal Spell Card from their Deck and places it on top of their Deck.
It can target itself, but there has to be a legal target in there to activate its effect. (Which there usually will be, but you could have been a weirdo and discarded 3 Destiny HERO - Dogma as the only D-HEROes in your GY or something.)
Ok, hold the hell up. I was just in a ranked match and I summoned this card on my opponents field and they were STILL able to use Enemy Controller. I'm pissed...
Blame the anime and their situational cards and Konami printing a lot of GX cards in a stupid way.
As written in YGO Wikia, in anime, this card was specially designed to take down "Destiny Hero - Plasma", according to Aster Phoenix. It defeats "Plasma" by changing the top card of the opponent's Deck, which is where "D - Force" would be present. In the anime, this negated the effects of "Plasma".
It was released in the ARC-V era in the TCG/OCG, but it appeared in the GX anime. (Same goes for Celestial.) He never used it in ARC-V, either. (Actually, aside from Polymerization, ALL the cards Aster used were new in ARC-V, unlike Alexis, Crow and Jack.)