R6250 Disappears Then Returns As DD-WRT?

Hello - today I got home from work to no wi-fi.  I went through the usual steps - unplug, wait plug back in several times with no luck.  After the third try I noticed in the list of nearby networks there was a "DD-WRT" with 5 bars.  Finding it hard to believe I was getting that strong of a signal from a neighbor, I entered my password and it took it.  I then disconnected the router and DD-WRT was gone from the list.  So, can someone explain what's going on here?  I did some basic searches and saw nothing that sounded like this scenario. How did my network disappear and come back under a new name?  Thanks in advance!!!