Jumbo Flan is immune to physical attacks and absorbs all elements (except Holy). It has Reflect that cannot be dispelled, but it is susceptible to Slow if the player bounces the spell off a party member (the member must have Reflect status).
Also when uses his Regen ability himself only lasts 10 turns.
When farming Jumbo Flan for Magic Spheres, the player will want to kill it as fast as possible. The fastest strategy initial is to max out Yuna's Magic Defense and Agility, therefore maxing Anima's corresponding stats as well. Anima should know Haste, Shell, Lancet or Curaga, and Dispel. Regen is also useful here.
The battle should be started by casting Reflect on one party member and bouncing Slow off of them to slow down the Flan. Then Anima should be summoned and buffed with Haste and Shell, optionally five boosts of Focus, for both fortified effects of cure spells and reduction of Jumbo Flan's offensive spells. After that Anima should use Pain 2-3 times, depending on her agility, each turn. If Jumbo Flan uses Regen it can be dispelled right away, but if the Pain attacks are doing enough damage the effect may be insignificant.
If using a regular party, the battle should still be started by slowing down Jumbo Flan. Then the party should get ready by casting Haste, Shell and Focus on everyone (and dispelling any characters of Reflect). The party should then proceed by Doublecasting Flare (preferably) or Ultima. Holy also works but cannot be doublecasted.
The characters that should be used are Yuna and Lulu as they boast the highest magic power. Lulu's fully powered Celestial Weapon also offers Magic Booster and One MP Cost effects which are perfect for this battle, and if one received Dark Matters from catching monsters for Arena, another weapon can be created with Break Damage Limit, One MP Cost, and Magic Booster; this being the fastest strategy final to defeat it.
Overdrives are effective because they are neither physical or magical, but due to Jumbo Flan's defensive stats, their damage is significantly reduced when compared to spells or Anima's Pain attack.
Flan is an open pastry or sponge cake containing a sweet or savory filling. A typical flan of this sort is round, with shortcrust pastry, usually coated with sweet syrup. It is similar to a custard tart or a South African melktert.