1) Arachnid Ambush

The PCs have been traveling and decide to stop by the local watering hole. It's called "Glittering Prizes," and the faded sign above the door depicts a treasure chest overflowing with gold and gems, with a golden sword sticking out.

It's unnaturally quiet inside, the people sitting at the bar or around tables all seem to be playing at merriment. Cards are held at awkward angles, drinks raised but never emptied, and there are no heated arguments or brawls. Eyes seem to swivel to the PCs but then snap back before they can confirm.

One of the patrons stands up and walks to the PCs with an awkward gait. He demands a specific treasure they have recently acquired, one that he shouldn't know they have. If they refuse, All the bar patrons tear off their human costumes with a sickening rip, revealing jet black chitinous human-sized bodies with eight legs, and faces with eight glowing green eyes and vicious mandibles. They screech in unison and attack the (hopefully) startled characters.

(Adjust the number of spider people to the size and level of the group. I used just one against a first level group of 5 characters, and it got owned big time.)

Spider-People
5 HP, Reach Weapons (long, pointed legs), Light Armor+ (12 AC)
+2 Awareness, +1 Cunning
Abilities:
1AP:  Leap up to the Ceiling (open)
1AP: Drop down (move and attack in one round, on the attack step)
2AP: Web Spray: Immobilize all opponents in one arena, unless they make a Cunning save (difficulty 7)
2AP: Poisonous Bite: When making a successful attack, the spider person can pull the target in and bite with their poisonous fangs. The target will take an additional poison damage unless they make a Commitment save (Difficulty 7) at the end of the round.