Sorcerer pits vampire against Lovecraftian horror, demonic hellspawn against mythological monster and MTG-like card battles against gameplay that veers between fighting for control of areas of the city, deckbuilding and rolling dice
This is the first colorless spell that produces an extra combat, and its repeatable
Perhaps the best example is Aang himself, who has a mono-White card in Aang the Last Airbender, a tricolor version in Aang at the Crossroads, and a four-color version that turns into a WUBRG creature in Avatar Aang/Aang, Master of Elements
Backup was just a particularly lovable mechanic in Limited, and I'm hopeful we have some cards that will play roles elsewhere
There's definitely a debate about which art is more iconic: the original from Ice Age , the Mercadian Masques version, or the version that first appeared in the Duel Decks