The most uneven pace in the chart, because its orbit is the most eccentric.
Pluto's orbit is eccentric enough that its time per sign varies from about twelve years to over thirty. It crossed Scorpio in eleven years and took thirty-one over Taurus. No other body in the chart is so uneven.
It is also inclined 17° to the ecliptic, far more than any planet, which is why its ecliptic latitude in a chart can be strikingly large.
Its 2006 reclassification changed nothing about the ephemeris — the position is the position. Astrology kept it; astronomy renamed it. This site plots it either way.
What it is
A dwarf planet since 2006, and the largest object in the Kuiper belt after Eris.