Pathfinder 1e Monster / NPC: Lurking Ray, Trapper

Trappers can grow to be 15 feet from tip to tip, and weigh nearly 2,000 pounds when fully fed.

Female lurking rays, known as trappers, are the masterminds of their race. Too large to fly (and often gravid with wriggling young), the intelligent trappers scrape themselves out depressions in the floor of regularly traveled chambers and then lie in them, changing their coloration and texture perfectly to blend with the rest of the floor, and sometimes even creating protrusions in the shape of items they know to be valuable to their prey creatures. When a lulled individual steps onto the trapper’s surface, the ray twists itself up around it, smothering and beating its victim senseless before drawing it into its maw for slow digestion.   Though quite intelligent even by human standards, trappers devote almost all of their mental faculties to perfectly remembering every sensory detail about their surroundings in order to make their chameleon-like disguises all the more cunning and difficult for their prey to resist.   Amorphous (Ex)
Lurkers above and trappers are immune to precision damage (like sneak attacks) and critical hits, and can move through an area as small as one-quarter their space without squeezing or one-eighth their space when squeezing.
  Constrict (Ex)
A creature with this special attack can crush an opponent, dealing bludgeoning damage, when it makes a successful grapple check (in addition to any other effects caused by a successful check, including additional damage). The amount of damage is given in the creature’s entry and is typically equal to the amount of damage caused by the creature’s melee attack.   Light Sensitivity (Ex)
Creatures with light sensitivity are dazzled in areas of bright sunlight or within the radius of a daylight spell.
  Smother (Ex)
When a lurker above grapples a target, it forms an airtight seal around its prey. A grappled target cannot speak or cast spells with verbal components, and must hold its breath (see Suffocation)