Asian forest scorpions, large, glossy black, heavy-clawed, and the standard counterexample to the fat-tail rule: thick pincers, thin tail, mild venom.
They are communal in most species, burrow readily, want humidity rather than aridity, and are about as forgiving as scorpions get. Frequently recommended as a first scorpion and the recommendation holds.
Species identification in the trade is close to meaningless. Animals sell as spinifer, silenus, swammerdami and several others largely at the vendor's discretion, and much of it is wild-caught Indian and Southeast Asian material sorted by size rather than taxonomy. Do not pay a premium for a species name in this genus.