Frank Oz slowly losing his mind during endless takes

As a supplement to yesterday's link to Emmet Otter's Jug-Band Christmas, here's an extended outtake of Frank Oz (as Ma) and Jerry Nelson (as Emmet) becoming ever more loopy and funny during take after take of a scene in the special.

(There's a few different bloopers at the start of the video but they're nothing special, so I linked directly to the good part.)