Charred Thunder Potato Gu

Fang Yuan first names the Gu while hunting a demonic female Gu Master, calling the earlier explosion a rank two grass Gu buried in advance, the Charred Thunder Potato, that detonates no matter who steps on it. ^{ch. 210}

Appearance

The unplanted fruit is finger-thick and dark green. When refined and fed primeval essence, it gives off a faint green light, slowly hovers, then drills into the ground. Buried in soil, that tiny grass Gu grows into a fist-sized potato. ^{ch. 213}

Form and rank

The fruits are Charred Thunder Potato Gu, a rank two Gu. After burial and growth, a matured one is fist sized and can explode from even a slight vibration. When refined and fed primeval essence, one fruit gives off a faint green light, hovers, then drills into the ground. ^{ch. 213}

Those fruits come from Charred Thunder Potato Mother Gu, a rank three Gu that looks like a potato with an uneven surface and tiny holes. Primeval essence makes green sprouts grow from the holes, blossom, and bear dark green finger-thick fruit. ^{ch. 213} Charred Thunder Potato Mother Gu also produces Charred Thunder Potato Gu. ^{ch. 256}

Effect

Once buried, the Gu grows with soil fertility. When any living being steps near it, vibration makes it self-detonate. ^{ch. 213} Bai Mo Xing later calls it an expendable type that absorbs energy from the ground to grow and explodes after vibration impact, with strong attacking power among rank two Gu. ^{ch. 217} It is an offensive Gu that cannot be moved once planted, which lowers its practical value. Layered burial can stack blasts strong enough that even thousand beast kings might not get off easy. ^{ch. 213}

Planting itself spends aperture primeval essence while soil fertility gathers into the Gu and it swells from a tiny grass Gu to fist size. ^{ch. 213} That growth cost is separate from any later feed schedule the novel never states for unplanted fruits.

Limits

It must be used in soil, and more fertile soil is better. On Bai Gu mountain, where there is no soil and the rocks are bone, it cannot be planted. ^{ch. 217} It is unstable in use: it needs to be planted, fails if nobody steps on it, and a forgetful planter can injure themselves. ^{ch. 222}

Early use

Chen Cui Hua buries many Charred Thunder Potatoes before her cave and later uses them against a twin-headed boar; Fang Yuan and Bai Ning Bing watch those traps go off. ^{ch. 210} After killing her, Fang Yuan takes a charred thunder bean mother Gu among her aperture Gu. ^{ch. 211} He and Bai Ning Bing then produce and bury many Charred Thunder Potato Gu in layered pits to kill grass-skirt monkey kings. ^{ch. 213} He later buries at least five in a black bear’s retreat path during the Bai clan hunt. ^{ch. 217}

Tie Dao Ku later reads an explosion site as almost a hundred Charred Thunder Potato Gu buried together, a trap that killed Tie clansmen during the chase after Fang Yuan and Bai Ning Bing. ^{ch. 220}

Northern Plains defense line

Path

Cited chapters describe the explosive grass Gu without naming a cultivation path for this Gu.