Minecraft riddles

Now an easy one.

Souls are trapped in me, and can never get out.

What am I?

If enough riddles are found I could make a minecraft animation about this

soul sand

obviously lol

Soul sand

Next riddle:

I fly high in the nether, and the ender dragon is my mortal enemy

ghast

Wither

2 mobs that naturally float in the nether: blaze, and ghast. Ghast dies in one hit kill. No. Blaze, dies real fast. No. It has to be wither

coolguy must of gotten it right...

Here's one:

The most ruthless of them all; the one that all players and creatures fear

I am also the rarest of all.

They think i am harmless; but as soon as I turn around, it is too late.

What am I?

Um can't be enderdragon, she is not considered harmless...

could be trap horses or spider jockeys?

I am also the rarest of all.

OH I KNOW.

Sheep when you first spawn. They're never around when you need them. I just wanna make a bed...

Nope. lol, but that's sure what it seems like. But there are plenty more rare mobs. But this mob actually has the LEAST chance of spawning out of all the mobs! And it is considered harmless... at first...

and sheep aren't ruthless... right?

Or ARE they??? 

Charged Creeper, 

Sometimes seems harmless at first... creepy and sneaky, not ruthless. Also pretty rare!

yknow what, I'll say it

it was the killer bunny

if it had high health, it could wreck the wither if it didn't fly

Can it even naturally spawn? 

yeah, but ultra rare