Wight of the Reliquary does not have summoning sickness.
You control at least one additional creature.
Steps
Activate
Wight of the Reliquary by tapping it and sacrificing another creature, causing you to search your library for a land card and put it onto the battlefield tapped.
When the land enters the battlefield,
Felidar Retreat triggers, creating a [token] creature token.
When the creature token enters the battlefield,
Intruder Alarm triggers, untapping all creatures.
Repeat.
Results
Put all lands from your library onto the battlefield tapped.
Near-infinite landfall triggers.
Metadata
In 8 decks according to EDHREC.
Bracket Tag
This combo has been estimated to be Exhibition (Bracket 1+).