Middle of Navarn Steppe at NPC Milden. There is also one at Valtara Mountains, north of the actual icon "Valtarra Mountains"

A big stone crab named Kamasylvia Scrub Stoneback Crab. Attack it and smaller adds will spawn, read below!

Hit the big one, and small spawn. Dont kill big one too fast

The big one can spawn small ones 2 times, and he drops 3 at the time, one of each at 70% hp and 30% hp
Kamasylvia Rough Stoneback Crab
Kamasylvia Herb Stoneback Crab
Kamasylvia Small Stoneback Crab

Kill the small ones AND use pickaxe on them BEFORE you kill the big one, or else they might despawn. (You can gain knowledge by gathering on monsters)

Do NOT drop the health of the big one too fast at the beginning, he might not summon extra at all if you do that.

Pull Big One, knock to 75% kill all the little ones, knock to 30% kill all the little ones.... Run away and reset and repeat.

Arkadaşlar Bu yengeç 1 büyük yengeçten doğuyor ve kolay ölen bir yengeç olduğundan çok düşük bir ap ile hatta ben yumruk ile saldırın bi süre sonra 3 yengeç atıyor ve yanınızda kazma da olsun. Ana yengeç ölürse yavrular direk ölüyor bilginize.

This is what they look like: