African wandering spiders, large and fast, in the family that contains the most medically documented spiders on earth, which sets the default: barely studied plus serious relatives equals full caution.
They are nocturnal surface hunters, containment-defined: vertical structure, cover, sealed maintenance, deliberate opening, no handling under any framing until the science says otherwise, and it has not yet said anything.
West and Central African supply arrives in rare pulses with soft identification, the trade is a few specialist sellers deep, and prices form on scarcity. The genus sells the wandering-spider experience with the risk profile unresolved, which is a niche for exactly the keepers who read that sentence as information rather than invitation, and the buyer pool is correctly that small.