Game unit design: a shield

[Bryan Lee]

I am trying to design a castle game where each fighting unit is an
individual person.  I'm trying to create a unit that represents a shield
that can be picked up, caried and used by any fighter.  It has 5 HP and
protects whoever is carrying it from 80% of attacks, absorbing the
damage itself and disappearing when it reaches 0 HP.  

I've read through the code in fantasy.g and cave.g and have copied
portions relating to fantasy.g's ring of protection and any thing else
that seems relavant.  At this point, I can't even get one of my fighters
to pick the shield up, let alone see if it behaves correctly.

What do you have to do to create a unit that behaves like an item?
Any help will be greatly appreciated.