  Ultraviolet and optical spectra of the hydrogen-dominated atmosphere white
dwarf star G238-44 obtained with FUSE, Keck/HIRES, HST/COS, and HST/STIS reveal
ten elements heavier than helium: C, N, O, Mg, Al, Si, P, S, Ca, and Fe.
G238-44 is only the third white dwarf with nitrogen detected in its atmosphere
from polluting planetary system material. Keck/HIRES data taken on eleven
nights over 24 years show no evidence for variation in the equivalent width of
measured absorption lines, suggesting stable and continuous accretion from a
circumstellar reservoir. From measured abundances and limits on other elements
we find an anomalous abundance pattern and evidence for the presence of
metallic iron. If the pollution is from a single parent body, then it would
have no known counterpart within the solar system. If we allow for two distinct
parent bodies, then we can reproduce the observed abundances with a mix of
iron-rich Mercury-like material and an analog of an icy Kuiper Belt object with
a respective mass ratio of 1.7:1. Such compositionally disparate objects would
provide chemical evidence for both rocky and icy bodies in an exoplanetary
system and would be indicative of a planetary system so strongly perturbed that
G238-44 is able to capture both asteroid- and Kuiper Belt-analog bodies
near-simultaneously within its $<$100 Myr cooling age.
