Spider

Tiny beast | CR 0 | Access Lvl 2

Bite. 5ft, +4 to hit. 1 piercing dmg + DC 9 CON save or 1d4 poison damage.

Spider Climb. The spider can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.
Web Sense. While in contact with a web, the spider knows the exact location of any other creature in contact with the same web.
Web Walker. The spider ignores movement restrictions caused by webbing.