Strange MySQL database that I can't select

This is nothing but a folder/file in database directory.

The default location for data directory is /var/lib/mysql on ubuntu.Go to that location(datadir) and find what is there in that folder if it not your database please move that to some another place.

If you need to find the location of data directory issue command on MySQL shell

SHOW VARIABLES LIKE 'datadir';
+---------------+-----------------+
| Variable_name | Value           |
+---------------+-----------------+
| datadir       | /db-data/mysql/ |
+---------------+-----------------+
1 row in set (0.00 sec)

Which will give you the location of data directory

OK, so it seems that his has occurred because someone has left some files (one called conf) in the MySQL user's home directory. Removing them has removed this weird database.