Arms Micron "Bulkfists" like Hulk hands that turn into a tiny version of Bulkhead himself. They were released in Japan in Capsules and in the UK in plastic packets.
There is also a clear blue version. But I've not got around to Photographing them yet.
Here is some more related images :
This is the arms Micron Arcee also lacking a bit for paint but I like the darker colour she is. Her miniature Arcee is supposed to be a sword but I think it looks better as a arm blaster myself.
Bulkhead is holding it in the established sword mode manner here :
I Hope that helps a little.