Banned
Worldgorger Dragon
Creature — Nightmare Dragon · {3}{R}{R}{R}
Rationale
Why banned
Worldgorger Dragon, looped with Animate Dead or Necromancy, repeatedly exiles and returns all of your other permanents to generate infinite mana and a game-ending payoff. Banned at the format's founding as an infinite-combo engine.
Oracle text
What the card does
! This card is currently banned in Premodern. The oracle text is shown for reference only.
Flying, trample When this creature enters, exile all other permanents you control. When this creature leaves the battlefield, return the exiled cards to the battlefield under their owners' control.
Format authority
Cited from premodernmagic.com
Per Martin Berlin's Premodern format-authority site: premodernmagic.com/rules . premodernmtg.com mirrors the canonical banlist within 24 hours of any update.
Full analysis
The combo, the data, and the new metagame
Banned 2003-05-26. Rationale: Worldgorger Dragon, looped with Animate Dead or Necromancy, repeatedly exiles and returns all of your other permanents to generate infinite mana and a game-ending payoff. Banned at the format’s founding as an infinite-combo engine. Source: Martin Berlin, premodernmagic.com.
See also: /worldgorger-dragon/