Nathan Fillion guest stars as a doctor in the most recent episode of Neil Patrick Harris' fun comedy web-series that explores his crazy Puppet Dreams. This is the second episode of the series and here's the description,
Welcome to the brain of one of the sickest puppeteers ever encountered - Neil Patrick Harris. In this episode, Neil's unique physiology causes a stir in the puppet medical community.
Make sure to look for the hilarious Dr. Horrible refference added to the short! I've enjoyed both episodes of the series so far, and I'm looking forward to seeing more.