It's not easy killing a god, unless you're a high level Destiny player that is, in which case it's possible to take on the Hive deity Crota all by your lonesome in The Dark Below's Crota's End raid.
In the video above we see The Legend Himself take on the entire thing by himself, the first player to have done so to date.
The aptly-named player achieves this impressive feat via a combination of skill and stealth (not all the enemies he faces die). The Legend Himself does die more than once, and he even admits he has no plan for dealing with Crota when he gets there, it's still a pretty fun 33 minute watch.
A word of warning though, The Legend Himself does note that it's probably not possible to do it at level 31.