Spooky Squash was difficult because it was complex and split your team, with two members having to Anchor the Guardian. Those Anchoring Zombies would be sitting ducks if the random wandering of the Spooky Squash brought him up into the rooftop- we lost a lot of those Hunts simply because of that one factor because we'd lose one of the Anchoring Zombies.
I think The Kings Day Out was one of the hardest because of a few factors; the high possibility of being frozen in place, the abundance of new players experiencing their very first Boss Hunt and the lack of Players able to play a Sunflower properly, or willing to play one at all.
A Banquet for Sasquatch had similar issues only with the chance of freezing replaced by the chance of burning to death.
