Tri-Point will counter with Mega Spark unless it is hit with an element it is very weak against. If Tri-Point uses Scan on a target, the target will be hit with Onrush the next turn. It is a massive, inevitable attack that ignores defense, often dealing 9,999 HP damage.
To find out Tri-Point's weakness, the player must Scan Tri-Point first to know if it's weak against either Fire or Ice. If it is weak against Fire, the party must attack with Fire attacks, which prompts Tri-Point to be weak against Ice, of which then the player must attacks with an Ice attack. Alternatively, since Mega Spark is Lightning-elemental, if it is possible to junction the characters' Elem Def-J to negate or absorb Mega Spark.
It may be useful to use Protect on the scanned character to mitigate the damage from Onrush.