Ratadrabik of Urborg | Boonweaver Giant | On Serra's Wings (and one other card)

Cards

Activate
Ashnod's Altar by sacrificing
Boonweaver Giant, adding ({C} magic symbol) ({C} magic symbol) .
When
Boonweaver Giant dies as a legendary creature due to
On Serra's Wings,
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
On Serra's Wings from your graveyard to the battlefield attached to the token.
Repeat.

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