Jade Flame

This strange, vibrant green fire burns everything that comes near it, yet the nature of its magic is such that a creature it burns cannot be harmed by other sources of heat for a limited time.

    Effect: A creature that enters a square of jade flame or that starts its turn adjacent to such a square takes ongoing 5 radiant damage per tier (save ends). However, until the creature saves against the ongoing damage, it has resist fire equal to 10 per tier.
    Usage: Jade flame offers the characters a choice. They can accept some constant radiant damage in return for protection against a potentially more dangerous threat. The characters might need to use jade flame to protect themselves before they race across a lava chamber or face another sort of fire hazard.

Published in Dungeon Master's Guide 2, page(s) 60.