Wut planes have the same frame type as the P-38 Lightning, but have two cockpits on top of eachother?

Question

its in the smithsonian air and space museum and i can't find it in any pictures

Answer 1

P-61 black widow

Answer 2

twin Mustang i guess the version was P 51 H -basically two mustangs bolted together edit it was designated F-82

Germans had similar design based on Bf 109

Germans also were trying the twin He 111 bomber

mining out the wiki provided following planes:

P 61 blackwidow, He 111 version Z used as a tug plane for giant gliders of messerschmitt, Me 609, and the Me 109 Z

Germans designated their twins with the letter Z meaning zwilling = twin