Had he only been Reverse Giraffe, Keith David could still have had a decent claim to being the best guest voice in the run of “Rick & Morty.” Add in a planet-saving dance of raised-up posteriors and his case has only grown with each passing season. It’s his particular blend of instant gravitas and ability to cut through any surrounding nonsense that makes him an ideal asset for a series that can often use both.Rick and Morty Season 1-6 Download.