Recently I learned about this fan project called MST3K vs. Gamera: Round 2, where the three Showa era Gamera films not used in the original series are riffed. I watched the first one Gamera vs. Viras the other night and it was pretty decent. Particularly notable is that it had an episode specific Doctor Who riff (as opposed to riff just generally alluding to Doctor Who). See if you can pick it out.

https://www.youtube.com/channel/UCAI-dPyGhck5LTXwu2dNVpg/videos