[imp] Apache running off with my CPU and RAM?

[Eli]

I've had a dedicated system to just IMP up for a few days now (about 5),
and it's been getting a few users here and there, nothing overly huge in
connections, however, about once a day I've noticed something real
weird:

USER       PID %CPU %MEM   VSZ  RSS TTY      STAT START   TIME COMMAND
root       356  0.0  1.2 10760 6228 ?        S    Aug16   0:00
/opt/apache/bin/httpd -DSSL
http     10286 85.1  2.3 15240 11488 ?       R    Aug19 656:52  \_
/opt/apache/bin/httpd -DSSL
http     11079  0.2  1.9 13468 9736 ?        S    06:43   0:16  \_
/opt/apache/bin/httpd -DSSL
http     11120  0.1  1.9 13200 9460 ?        S    07:01   0:10  \_
/opt/apache/bin/httpd -DSSL
http     11135  0.2  1.9 13656 9888 ?        S    07:14   0:11  \_
/opt/apache/bin/httpd -DSSL

That one process, using up 85% of my CPU, and about 11MB of RAM...
Apache can't kill it (it doesn't respond to SIGTERM) on it's own; it
doesn't show up at all in Apache's server-info list at all.  I have to
manually kill it with a SIGKILL, and then Apache is fine for a while
(not sure exactly when the process starts chomping CPU/RAM) until this
process turns up again.  Not sure if this has anything to do with it,
but the process that sucks CPU/RAM is always the first child under the
root process for Apache.

We are running:
Pentium III 1GHz CPU, in a server with 512MB RAM
Apache/1.3.26 (Unix) FrontPage/5.0.2.2623 mod_perl/1.27 PHP/4.2.2
mod_ssl/2.8.10 OpenSSL/0.9.6d

If anyone needs more info, I can provide them with a URL to the servers
PHP info page, as well as system info if required.

Eli.