That is cool… A u-boat with tracks…
Well, back to the straight armored classicism, honorable ladies and gentlemen! 
It is my turn again, therefore tell me, please: what kind of a tracked contrivance is this?
Quad fifty-cal AA guns on an M-36 platform? Though the platform doesn’t look long enough to be an M-36…
M 36 with quad 0.50 inch AA machine guns, my dear Prime Minister? No, definitely not!
After all - since when M36 has a trailer-idler wheel positioned as an added ordinary road wheel, if I may ask? Moreover, where are those well-known, distinctive perforated barrel supports on those alleged Browning 0.50 heavy machine guns? 
Hmmm… the pre-1945 Socialist Federal Republic of Yugoslavia flag painted on the side may be a subtle hint as to where you got this photo from. Sadly I’m not very hot on armoured vehicles, but knowing you it’ll be suitably obscure
M3 with flak gun
Hawkeyes, my dear Mr. Pdf 27! What a pity that you are not an armored vehicles fan. However, I am assuring you that my personal “Rarity Cabinet” is fulfilled with similar aerial oddities as well.
And yes, my dear Herr Major – that is the correct answer: M3A3 equipped with the 2cm Flakvierling 38, snapshoted in 1944 as a specialized component of the 1st Tank Brigade of the Yugoslav Army. Only four previously heavily damaged M3s (those with a completely devastated turret) were converted in this manner.
Your turn!
Well, at least I tried…
seems to be flakvierling on stuart chassis, I know israeli likes to mix and match between ex allied and ex german arsenals, or just simply use them both
Ouch am late,…
OK… I got new one for you!
And I have the answer for you as well, my dear Herr Major: 15cm Panzerwerfer 42 auf Selbstfahrlafette Sd.Kfz.4/1 Maultier
Aw, I was going to say that, because that’s one of the few I’ve recognized in this thread…
Librarian goes next!
Thank you, my dear Herr Major. And so, here we have another armoured mystery:
Could you guess the gadget?
looks french…
Wait, its the Renault BO-18 Bottle opener!
Sorry, my dear Major: aforementioned breathtaking French model is not that one we have here!
hmmm… it does look like a bottle or can opener…
The gadget in question is a WW1-era device to assist in crossing trenches, usually known as a tail.