In this video, YouTube user nik282000 shows us what happens when lithium metal burns -- in slow motion. Using a 300fps camera (10x slower than realtime) and a macro lens, we can see the process of lithium burning, passing through several bizarre phases until it resembles a hunk of charred cauliflower. Have a look!
Note: things don't really get cool until just before the 2-minute mark. Give it time.
If you want a (shaky) view of what this looks like in realtime, check out some guy burning lithium and don't try it at home -- the fumes and touching the lithium are dangerous.