While bishops are most often seen at confirmation ceremonies, it is possible for a priest to perform a confirmation in certain cases.
The Code of Canon Law explains how, "The ordinary minister of confirmation is a bishop; a presbyter [priest] provided with this faculty in virtue of universal law or the special grant of the competent authority also confers this sacrament validly."
Priests typically perform the sacrament of confirmation each year at the Easter Vigil, when children and adults are received into the Church.
However, priests can also perform confirmation in the place of bishop, such as for a large group of young people, if he receives the bishop's permission.
This will often happen when the bishop is older or suffering from ill health, or when a parish is in an isolated location that the bishop is unable to reach.
In the early Church, bishops were the only ones who confirmed individuals, but as the Church grew, bishops allowed priests to celebrate various sacraments, including confirmation.
While it may look strange to have a priest confirming individuals, it is permitted by the Church.