How do you introduce a scary object to a horse from the ground?

Introducing a scary object from the ground begins at whatever distance allows the horse to notice the object without entering a full flight response — and that distance varies considerably between horses and between objects, so finding it requires watching the horse's response rather than assuming a standard starting point. Stand with the horse at the distance where it is alert and clearly aware of the object but is still able to process information rather than operating in pure flight mode: the head is up and attentive but not rigidly extended, the nostrils are working but not flared maximally, the horse's feet may be planted but it is not actively trying to bolt. At that distance, allow the horse to look. Do not create additional pressure — no forward movement request yet, no touching the object, just standing while the horse processes what it is seeing. Watch for the first signs of relaxation: a breath released, a slight lowering of the head, a shift of weight, a lick or chew. When any of those appear, reward them as the first correct response by simply staying quiet and letting the horse stand. From that relaxed moment, ask for one small step toward the object — not a full approach, just one step — and reward it with a pause and a release of any pressure. Continue this progression: one step at a time, pausing after each to let the horse's emotional state settle before asking for the next. The horse directs the pace of its own approach through the quality of its emotional responses, and the handler's job is to read those responses accurately and match the asks to what the horse can manage. When the horse arrives close enough to sniff or touch the object with genuine curiosity rather than frozen tension, the first major goal of the groundwork introduction has been achieved.