Aphrodite

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.

Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one creature. Hit: 1 piercing damage, and the target must succeed on a DC 9 Constitution saving throw or take 2 (1d4) poison damage.

Venom spit. ranged attack +4 Hit. 2d4 acid damage and the target must  succeed on a dc 14 or the armor is melted and there ac is halfed per hit. 

 Slam. Melee attack +4 Hit 2d6 force damage  upon hit the enemy must make a dc of 15 strength check or be knocked prone.

upon reaching critical damage it screechs and summons 2d20 smaller spiders for back up. upon summoning it now gets even more aggressive. upon summons it gains a +3 to ac and +2 to hit. the summons have 1d12 hp and all they do is try to web up the party a acrobatics check of dc15 or become entangled and then a strength check of 18 to break free or become immobilized untill freed by a fellow party member or you break the web.