False appearance The sac appears to be a tangeld ball of string, twigs and dirt. Someone who can see the sac, can identify it with a successful DC 15 Intelligence (Arcana or Nature) check.
Fragile A creature who enters the spythronar sac's space must succeed on a DC 10 DEX Save or the sac is destroyed.
Lightning Release When the sac is destroyed it releases lightning in a 10-foot radius. A creature who destroyed the sac by entering the space, receives no saving throw. Other creatures in that area must succeed a DC 10 DEX SAave or take 1d8 lightning damage. EAch spythronar swarm and web in this area instead gains Advantage on its next attack roll.
Shocking Birth When a sac takes lightning damage from a source other than another spythronar, it hatches, transforming into a spythronar swarm with half the normal HP. This swarm rolls Initiative and denters combat.