Ratadrabik of Urborg | Boonweaver Giant | In Bolas's Clutches (and one other card)

Cards

All permanents on the battlefield (
In Bolas's Clutches attached to
Boonweaver Giant).

Activate
Shilgengar by sacrificing
Boonweaver Giant.
When
Boonweaver Giant dies as a legendary creature due to
In Bolas's Clutches,
Ratadrabik of Urborg triggers, creating a token copy of
Boonweaver Giant that is a 2/2 Zombie in addition to its other types.
When the
Boonweaver Giant token enters the battlefield, it triggers, returning
In Bolas's Clutches from your graveyard to the battlefield attached to the token.
Resolve the
Shilgengar ability.
Repeat.

This combo has been estimated to be Exhibition (Bracket 1+).