Immutable Form.

The spider is immune to any spell or effect that would alter its form.

Magic Resistance.

The spider has advantage on saving throws against spells and other magical effects.

Magic Weapons.

The spider's weapon attacks are magical.

Actions

Multiattack.

The spider makes two slam attacks.

Slam.

Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 19 (3d8 + 6) bludgeoning damage.

Slow (Recharge 5–6).

The spider targets one or more creatures it can see within 10 feet of it. Each target must make a DC 17 Wisdom saving throw against this magic. On a failed save, a target can't use reactions, its speed is halved, and it can't make more than one attack on its turn. In addition, the target can take either an action or a bonus action on its turn, not both. These effects last for 1 minute. A target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Jade Giant Spider