1) Sturmgewehr44 Krummlauf

This weird bent barrel attached to riffle allowed to shot from safe position (behind wall)

2) Bat bomb

Probably the weirdest weapon of all time. The bomb cointained hibernating Mexican Free-Tailed Bats each "wearing" small incendiary bomb.  After drop, the bats would spread and hide in buildings. Later, built-in timers would ignite bombs and cause fire.

3) Anti-tank dog

The dogs were trained to carry "backpack" full of explosives to tanks. However, dogs very often ran away from the target because of fear. 

4) Yokosuka MXY7 Ohka

MXY7 was rocket powered kamikaze aircraft know also as Suicide Attacker. "Missle" contained explosives instead of engine. The pilot would glide towards the target and when close he would launch solid-fuel-rockets and hit the ship he wanted to destory.

5) Fu-Go

Fu-Go (fire balloon) was made paper and latex with  incendiary  weapons attached to it.

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P.S. I'm sorry for my English, it's not perfect yet :)