A dangerous boss in high levels, Jumbo Cactuar has attacks that mirror the regular Cactuar's attack, 10,000 Needles, but it is only used for countering. Its Ker Plunk hits the whole party.
When Jumbo Cactuar is on the last 5% of its health, a message will display: "Jumbo Cactuar is hesitating...". This means the Jumbo Cactuar is attempting to flee, so players have to unleash as much damage as possible to defeat it. Jumbo Cactuar will succeed in running away if less than 2% of its HP remains.
Jumbo Cactuar is weak against Water. Squall'sRenzokuken has a special animation for Jumbo Cactuar and it always does 7 hits; it will dance around in a comical way while Squall runs up to the Jumbo Cactuar and stands on its head while attacking it.
One of the fastest ways to defeat Jumbo Cactuar, especially after the "Jumbo Cactuar is hesitating..." message has been displayed, is to summon Cerberus—or cast Triple—and cast Water three times in succession, especially with someone with good Magic junctions.
Because of Jumbo Cactuar's 10,000 Needles attack, it's easy to use Limit Breaks when reviving characters with Phoenix Downs or Life spells, but it might be smart to dedicate one team member as a healer and keep them in high health throughout the battle, as Jumbo Cactuar's Ker Plunk can wipe out the entire party at low health.