Totally Not GG
Scout by Air: This bog is thick, murky, and mostly uninhabited, Perception DC 20: Something very large is moving in the swamp.
Scout by Land: This swampy area is mostly difficult terrain and all slow going. Periodically you see signs warning in common, beware of the Dragon! DC 15 Survival notices Quicksand, failure results in getting caught.
As you trudge through the thick swamp, sticking to the shallow areas, the sound of displacing water fills your ears. From the bog rises a Snake with fangs the size of your forearm and jet black wings with claws.
Giant Half-Dragon Constrictor Snake
CR 5XP 1,600
Advanced giant constrictor
N Large animal
Init 2 Dex, 28)
Fort 11 plus grab), 2 Claws 11)
Space 10 ft. Reach 10 ft.
Special Attacks constrict (1d8+11)
Breath Weapon 60 ft line of Acid (7d6, Ref 19)
Str 33, Dex 15, Con 22, Int 3, Wis 12, Cha 4
Base Atk +5 CMB +13 CMD 25
Feats Skill Focus (Perception), Toughness, Improved Natural Attack (bite), Great Fortitude
Skills Acrobatics +15, Climb +15, Perception +12, Stealth +7, Swim +15; Racial Modifiers +4 Perception, +4 Stealth, +8 Acrobatics
At first there appears to be no loot, however if the PC’s detect magic or cut open the snake, they find the remains of an adventurer with a +2 Ring of Protection, Bouncing Metamagic Rod, Catching Cape, Ring of the Ram with ten charges.