I play a decent amount of hearthstone and lately I've been using Kingsbane rogue deck in the current standard. I'm currently rank 12 (hoping to get to 10 by the end of the season), but I have found that one card royally screws my deck if its played on turn 6. Now, I personally get salty when one card beats me, but at the same time I love trying to overcome the challenge. Its not impossible to win if this card is played, but it makes it significantly harder. But without further adieu, here is the card that can screw Kingsbane rogue:
This card isn't a bunch of randomness which has plagued hearthstone in recent expansions.
If this gets dropped early, I can potentially loose 2 major buffs to Kingsbane from Deadly Poison being destroyed. It also destroys solid removals/Kingsbane refreshs from Doomerang.
Here is a link to the decklist I use: https://www.icy-veins.com/hearthstone/kingsbane-rogue-deck-list-guide