Body Launderer | Felidar Guardian | Mikaeus, the Unhallowed

(and one other card)

Activate
Altar of Dementia by sacrificing
Felidar Guardian.
When
Felidar Guardian dies, its undying ability and
Body Launderer's first ability trigger.
Resolve the
Body Launderer trigger, causing it to connive.
Resolve the
Felidar Guardian trigger, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
When
Felidar Guardian enters the battlefield, it triggers, targeting
Body Launderer.
Holding priority, activate
Altar of Dementia by sacrificing
Felidar Guardian.
When
Felidar Guardian dies,
Body Launderer's first ability triggers, causing it to connive.
Resolve the
Altar of Dementia ability from step 6, causing target player to mill cards equal to
Felidar Guardian's power.
Resolve the
Felidar Guardian trigger from step 5, blinking
Body Launderer.
Resolve the
Altar of Dementia ability from step 1, causing target player to mill cards equal to
Felidar Guardian's power.
Activate
Altar of Dementia by sacrificing
Body Launderer.
When
Body Launderer dies, its undying and second ability triggers.
Resolve the undying trigger, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
Resolve the second
Body Launderer trigger, returning
Felidar Guardian from your graveyard to the battlefield.
When
Felidar Guardian enters the battlefield, it triggers, blinking any other permanent you control.
Resolve the
Altar of Dementia ability from step 11, causing target player to mill cards equal to
Body Launderer's power.
Repeat.