Actions

Bites Melee Weapon Attack: +5 to hit, reach 0 ft., one creature in the Swarm's space. Hit: 4d4 piercing damage and 2d8 lightning damage, or 2d4 and 1d8 for piercing and lightning respectively if the Swarm has half or fewer HP.
Weave (4/day) The Swarm weaves webbing covering a 5-foot square. the Swarm can then give up 1 HP to create a sac in that space. If the Swarm's webbing covers a 10-foot square, it can give up 23 HP as part of the same ation, reating a Spythronar Web with the same number of HP. The swarm can't drop to 0 HP to create a sac or web. IF the Swarm weaves an incomplete web, that web is a normal web rather than a sentient montstrous one. A creature that enters this normal web's space must succeed on a DC 10 STR Save or become grappled (escape DC 10) and Restrained while grappled in this way. Each 5 ft. square of this web has AC 10, 5 HP and the same immunities etc. as a Spythronar Web.