Solo

For the purposes of encounter building and rewards, a solo monster counts as five standard monsters.
    ✦     Combined with another role (a solo lurker, for instance) but contains elements of other roles
    ✦     Deals five times the damage of a standard monster
    ✦     Lasts five times as long as a standard monster

Tip: Use one solo monster as an entire encounter, or pair one with minions or one or two standard monsters.

Published in Rules Compendium, page(s) 288.