Activate Goblin Sharpshooter by tapping it, creating a copy of the creature token.
Activate Altar of Dementia by sacrificing a creature token.
When the creature token dies, Goblin Sharpshooter triggers, untapping itself.
Resolve the Altar of Dementia ability, causing target player to mill cards equal to the sacrificed creature's power.
Repeat from step 2.
This clever loop turns Ghired, Mirror of the Wilds into an engine of endless duplication, granting your nontoken creatures an active ability to clone tokens that arrived this turn. You feed those freshly minted copies directly into Altar of Dementia to mill your opponent out of the game. Every time a sacrifice occurs, Goblin Sharpshooter's static death-triggered ability untaps it, allowing its tap ability to repeat the process infinitely and fuel the whole machine.