Rogue Database Appears in MySQL Show Databases - mysql

Question

I see today that
show databases
displays an unknown database:
(msl_ampcs_v4_0_0_2g)> show databases;
+----------------------+
| Database |
+----------------------+
| information_schema |
| #mysql50#.ssh |
| global_lad
Normally when I see something like that it is due to a bad file in /var/lib/mysql:
-rw-r--r-- 1 mysql mysql 1663 Mar 17 2011 /var/lib/mysql/ca-cert.pem
drwx------ 2 mysql mysql 4096 Jun 18 15:00 /var/lib/mysql/global_lad
drwx------ 2 mysql mysql 4096 Jun 18 15:00 /var/lib/mysql/global_lad_unit_test
-rw-rw---- 1 mysql mysql 3231711232 Aug 22 07:20 /var/lib/mysql/ibdata1
-rw-rw---- 1 mysql mysql 5242880 Aug 22 07:20 /var/lib/mysql/ib_logfile0
-rw-rw---- 1 mysql mysql 5242880 Aug 21 16:25 /var/lib/mysql/ib_logfile1
-rw-rw---- 1 mysql mysql 5 Feb 21 2013 /var/lib/mysql/istsdb2.jpl.nasa.gov.pid
-rw-rw---- 1 mysql mysql 4596466 Oct 15 2010 /var/lib/mysql/istsdb2-slow.log
drwx------ 2 mysql mysql 4096 Jul 13 2011 /var/lib/mysql/msl_ampcs_v2_0_0
drwx------ 2 mysql mysql 4096 Jul 21 2012 /var/lib/mysql/msl_ampcs_v3_0_0
drwx------ 2 mysql mysql 4096 Jun 20 02:55 /var/lib/mysql/msl_ampcs_v4_0_0
drwx------ 2 mysql mysql 4096 Sep 5 19:45 /var/lib/mysql/msl_ampcs_v4_0_0_2g
drwx------ 2 mysql mysql 4096 Sep 30 2010 /var/lib/mysql/msl_gdsdb_v5_0
drwx------ 2 mysql mysql 4096 Jan 19 2011 /var/lib/mysql/msl_gdsdb_v5_5
drwx------ 2 mysql mysql 4096 Nov 21 2011 /var/lib/mysql/msl_gdsdb_v5_6
drwx------ 2 mysql root 4096 Mar 23 2010 /var/lib/mysql/mysql
srwxrwxrwx 1 mysql mysql 0 Feb 21 2013 /var/lib/mysql/mysql.sock
-rw------- 1 root root 841 Jun 10 2010 /var/lib/mysql/nohup.out
drwx------ 2 mysql mysql 4096 Feb 5 2013 /var/lib/mysql/pdpp_automation
-rw-r--r-- 1 mysql mysql 1310 Mar 17 2011 /var/lib/mysql/server-cert.pem
-rw-r--r-- 1 mysql mysql 1679 Mar 17 2011 /var/lib/mysql/server-key.pem
But nothing like that is present. The nohup shouldn't be there. But
#mysql50#.ssh
does not appear.