Doubled in 5♠

On the second board of a two board set after giving away a top on the first. You doubled a seemingly ridiculous 5♣ contract that wasn't. It made 12 tricks when "someone" misdefended. You hold this magnificent selection:

♠	Q T 7
♥	5
♦	A Q 4
♣	A K Q 7 5 4

and partner opens 1♠! There's not much you want to know about other than the three key cards you're missing, 4NT. 5♦ from partner showing 1 or 4 is a cold shower. Sadly you sign off in 5♠ which gets doubled on your left.
The opening lead is a small spade, partner plays small and lefties knave holds. Stomach churning I couldn't look away from the rest of the hand. That's right, LHO doubled holding ♠AKJ and no other tricks. Steaming profusely we drag out the score sheet:

Contract	Declarer	Result	N/S	E/W
6♠x	S	-2		500
6♠x	S	-2		500
5♠	S	-1		100
5♣	N	-2		200
6♠x	S	-2		500
5♠x	S	-1		200
6♠x	S	-2		500
6♠	S	-2		200
6NT	N	-3		800
6♠x	S	-2		500

That's right, freely bid to 5♠, caught an unlucky double, went down one, 78%.