Banned
Flash
Instant · {1}{U}
Rationale
Why banned
Flash lets you put any creature onto the battlefield for a fraction of its cost — sacrificing it immediately if you can't pay the difference — which turns it into a free, instant-speed engine for explosive and unfair combo starts. Banned at the format's founding.
Oracle text
What the card does
! This card is currently banned in Premodern. The oracle text is shown for reference only.
You may put a creature card from your hand onto the battlefield. If you do, sacrifice it unless you pay its mana cost reduced by {2}. 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: Flash lets you put any creature onto the battlefield for a fraction of its cost — sacrificing it immediately if you can’t pay the difference — which turns it into a free, instant-speed engine for explosive and unfair combo starts. Banned at the format’s founding. Source: Martin Berlin, premodernmagic.com.
See also: /flash/