The Laggy-san is an NPC who wanders around Bes Pelargic. Unlike most NPCs, the Laggy-san will respawn immediately or almost immediately after being killed, appearing in some (apparently random) part of the city. Its equivalent in Ankh-Morpork is The LAG.
Yes, this is the real thing, the lag that always bothers YOU! Kill it so you can shout "Watashi sozedu zo NEGON!" It is in good shape. It is standing. On its chest is a handwritten sign which reads: "Will LAG for food". Wearing : a "Will LAG for Food" sign and a gold ring.
The sign it wears:
This is a sign that belongs to the Laggy-san. Something about it seems heavy and ponderous, though it doesn't appear to weigh that much. It appears to have something written on it. It is in excellent condition. > read it You read the "Will LAG for Food" sign: Written in flowing script in Agatean: Will LAG for Food
This ring looks like any other ring, but feels strange to the touch. It appears to have something written on it. It is in excellent condition. > read it You read the gold ring: Written in flowing runes in Agatean: Three blossoming rings For Deadly Pings of Winter Behind Autumn's screen, Seven for Packets Lost and Never Found Again Like Spring's final bloom, Nine for the High Speeds, Rarely seen by human eye In Winter's dark night, One for the Great Lag On once blooming Discworld ground Like leaves in Autumn In the Servers' Web Like unseen Winter blizzards Where the Routers lie. One Lag to slow them Like bees on a Summer's day One Lag to scare them, One Lag to stall them Like stagnant June air, and in The net ensnare them In the Servers' Web Like unseen Winter blizzards Where the Routers lie.
Wearing this ring will give you the message, "You feel like you have trouble moving..." and removing it will give the message, "You feel able to move at normal pace again.". However, it's not clear whether it actually slows you down at all.