Bonehoard

Corpses. When first encountered, a bonehoard has a mycosynth net that contains the corpses of 1d6 + 3 Medium or smaller creatures. 

While it has at least one corpse in its net, the bonehoard can use a bonus action to do one of the following:

• The bonehoard rapidly uses its corrosive claws to flay and consume the flesh from one corpse in its net and instantly regains 11 (2d10) hit points. Only the bones of the creature remains. Any nonmagical objects on the corpse are expelled from the bonehoard in its space, while magical objects remain in the net.
• The bonehoard animates one corpse in its net, turning it into a skeleton. The skeleton appears in an unoccupied space within 5 feet of the bonehoard and acts immediately after it in the initiative order. The skeleton acts as an ally of the bonehoard and other phyrexian creatures.

Mycosynth Webbing. The bonehoard can create a spider-like webbing from the living metal called mycosynth. As an action, the bonehoard weaves a net made of mycosynth webbing that it carries with two of its legs. The webbing is an object with 15 AC, 25 hit points, and immunity to psychic damage in addition to the bonehoard's damage resistances and immunities. A net can carry the corpses of up to 10 dead creatures of Medium size or smaller. 

Spider Climb. The bonehoard can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Phyrexian Nature. A phyrexian does not need to sleep, eat or drink, or breathe.

Multiattack. The bonehoard makes three claw attacks and uses either Capture Net or Net Slam in any order.

Claw. Melee Weapon Attack: +5 to hit, reach 10 ft., one target. Hit: 9 (2d6 + 2) slashing damage plus 14 (4d6) acid damage.

Capture Net. Melee Weapon Attack: +5 to hit, reach 10 ft., one target. Hit: The target takes 9 (2d6+2) bludgeoning damage and if it is a creature it must succeed on a DC 15 Strength or Dexterity saving throw (target's choice) or be added to the bonehoard's mycosynth net (if there is space left). While in the net the creature is considered restrained. A creature can only be freed from the net by destroying it (see the mycosynth webbing trait) or by magical means.

Net Slam. Melee Weapon Attack: +5 to hit, reach 15 ft., one target. Hit: The target takes bludgeoning damage equal to 4d6 + 2 for each corpse in the bonehoard's mycosynth net. Any creatures inside the net are automatically hit by this attack. If the bonehard has at least 5 corpses in its net, the target and all creatures within 5 feet of it must also succeed on a DC 15 Strength saving throw or be knocked prone.

Harvest the Dead. The bonehoard grabs one unsecured dead creature of Medium size or smaller that is within 10 feet of it and stuffs the corpse into its mycosynth net, along with any equipment the corpse is wearing or carrying. The remains can be used with the Corpses trait.