Silver rat ring
What is it?
You recognise the silver rat ring to be a piper's ring. This is a thick silver band, embossed with a circle of three rats biting on each other's tails. Each rat has two tiny red rubies for eyes. <number> of its eyes glow a dull red. It emits a slight octarine glow. It is in excellent condition.
It appraises as:
It is made of silver and appears to be a piece of jewellery. It is in excellent condition.
What does it do?
You can wear the ring, and if you twist it and have sufficient skills (probably ma.it.wo.ring, a bonus of around 150 should be fine), you will summon a rat that will protect you. This rat is a lot tougher than normal rats, though. Multiple rings can be used simultaneously but it seems like each ring can only support one rat at a time unless this changes with a high bonus.
The number of charges seem to be equal to the number of glowing eyes on the ring.
When the ring is twisted, the following happens:
You twist the silver rat ring. One of the eyes on the silver rat ring winks out. A confused rat scuttles in. The confused rat starts to protect and follow you, eyeing its surroundings confusedly.
The summoned rat
The summoned rat isn't always confused, it can have other descriptors. The rat looks like this:
This is a confused-looking rat with glowing red eyes. It moves with unusual agility for a rat, every motion tightly controlled as if by an outside source except for the deep confusion in its ratty face. It looks like it has absolutely no idea why it's following <Name> around and protecting him from attacks. It is in good shape. It is standing.
The summoned rat is safe from the owner casting Pragi's Fiery Gaze:
The fire fails to harm the confused rat[...].
Dwarves will attack the rat on sight..
An angry dwarf warrior arrives from the northeast. The angry dwarf warrior moves aggressively towards the confused rat!
... But this rat will fight back, and can use the trip command:
The confused rat bites the angry dwarf warrior in the left foot. The angry dwarf warrior chops her large axe into the confused rat's left rear leg. The confused rat trips the angry dwarf warrior, causing her to stumble slightly.
It will only stay for a few minutes, after which it runs away:
The glow in the confused rat's eyes winks out and it immediately scuttles away in a panic.
How do I get one?
In the Rat Farm you will sometimes encounter a rat king. Once the rat king is defeated, the rats that scatter leave behind a silver rat ring. The ring always has the same amount of glowing eyes as the number of tails that the rat king had. This seems to always be between four and six.