From Pathfinder Impossible Magic, which isn't enabled.

Lunging Spellstrike

FEAT 10

Activity 2 actions

Prerequisites Spellstrike; twisting tree hybrid study

Requirements You’re wielding a staff.

Your spell unwinds the structure of your staff to make it exceptionally long, or even separate it into shards held together by magical power.

Make a Spellstrike with a staff, with a spell that isn’t a cantrip or focus spell. Increase the staff’s reach by 5 feet × the spell’s rank.

Pathfinder Impossible MagicORC