Mecha-Merc
Appearance - A kind of exo suit that goes around the arms and up the shoulders
Stats - +20% vs buildings, hidden maxhealth non buffed +<35> max hp, ubercharge rate bonus for healer +10% uber rate on healer, Once reaching 100% rage (rage gained by doing damage to buildings, lost by taking damage from players) you can gain an aura of crits for 5 seconds, -10% attack speed, crits do no damage.
The idea of this weapon is to be a thing to use while uber'd and a support weapon for a team push. The crits are useless for the heavy himself but when used with a group it can be devastating.