On ovoids of O(5,q)

This article is about ovoids of the generalised quadrangle O(5; q) and, equivalently, spreads of the generalised quadrangle Sp(4; q). In a less than conventional way the quadrangles are represented in the field GF(q(4)) which allows some amount of computation to be done. It is shown that an ovoid of O(5; q) meets an elliptic quadric in 1 modulo p points.