What does "blocked=-2" mean? I'm trying to create an index on a pretty big table (over 8 million rows).

The index creation was taking over 10 minutes, so I selected from master..sysprocesses from my process spid:

spid    kpid    blocked waittype    waittime    lastwaittype    waitresource        dbid    uid cpu physical_io memusage    login_time                  last_batch              ecid    open_tran   status      sid             hostname        program_name                                    hostprocess     cmd             nt_domain   nt_username     net_address     net_library loginame    context_info    sql_handle  stmt_start  stmt_end    request_id
62      11836   -2      0x0003      11762       LCK_M_S         TAB: 5:427148567:0  5       1   0   0           3           2016-01-03 10:03:39.217     2016-01-03 10:15:41.013 0       1           suspended   0x010500...     MyPC            Microsoft SQL Server Management Studio - Query  9636            CREATE INDEX    MyDom       Saul            xxx             LPC         MyDom\Saul  0x000...        0x0100...   522         776         0


What is that "blocked = -2"?  Why is my index creation not working?  And how do I repair this?
This is documented in sys.sysprocesses (Transact-SQL):



You can find more information and possible actions to take in the duplicate question:


Dealing with Negative Session ID Denials in SQL Server  
How It Works: Orphan DTC Transaction (Session/SPID = -2)
Orphaned MSDTC transactions


In some cases, after proper investigation, it may be appropriate to configure SQL Server to presume that any in-doubt distributed transactions have aborted, using sp_configure.