Warp Cloak
This is a small rug-sized piece of fabric that opens a pocket dimension. It is not a Cloak that is worn. Each cloak in existence, when unrolled, warps open a dimensional aperture into a specific pocket-dimension (Judge's discretion as to which dimension). Once rolled up again, the pocket dimension is sealed off.
These were used quite effectively by Umar's troops in the war against the rebels in the Dark Dimension. The guards would hide themselves until a force of rebels would attack their caravan, stronghold, etc., then spring out and snap open the cloaks. Their Warp Cloaks opened into a dimension that was full of horrible monsters. The creatures would leap out and attack the rebels (they never attack the holder of the cloak).
It is presumed that a character who is enwrapped in such as cloak would automatically be dropped into the dimension it warped into. It is conceivable that some Warp Cloaks randomly access dimensions, instead of the same dimension every time. This could be quite a surprise for a character expecting a monster to charge forth, only to find something completely different.