Mining The Crystal Quarry: Mining Scourge
Even in multiplayer, Stifle will save your butt. The most promising use I can think of is to counter one of your own activated or triggered abilities. Notably, consider that this ability counters upkeeps and cumulative upkeeps, as well as 187 abilities, morph abilities (obviously), cycling abilities (either the card draw or any triggered abilities, but not both). It will save you from Pernicious Deed, Powder Keg, Strip Mine, creature-based abilities such as Willbender and many others. Most notably, casting this in response to putting Phage the Untouchable into play other than from your hand would, as it currently reads, counters the”you lose the game” clause. Moreover, this can counter the”return to play” trigger on cards like Astral Slide. Can you seriously ask for more?