Boss Fight: Garagakkal: HELP!

[Nimor Starseeker]

So following the advice of many here on this forum, I decided to let my group level up to level 3 before the Garagakkal boss fight at the end of book 1 in the Dead Suns adventure path.

My group is 4-6 players, but usually only 4 at a time because not everyone can make it for our weekly game night.

This time; ALL of the players can join in, so I have 6 lv 3 Players going up against the Garagakkal. Now I need to make the Garagakkal challenge harder. How do I do this?

The fight is supposed to be at least very hard, and now the APL is 4, and the challenge rating should be brought up to at least 6, possibly 7.

Normally it would be APL 2 vs the Garragakkal CR 5.
-Maybe move the combat inside the Sunrise Maiden spaceship? The monster would have a good time phasing through the walls, scaring the players, creating suspense on where it will show up next!
-Adding anbother Garragakal woould be to much, the players have not had the opportunity to buy new equipment.
-Adding a malfunctioning security bot to the ship? The Monster and the Bot.

I can budget in an extra 800 XP or 1600 XP for more monsters/dangers.

[Garretmander]

A trap to possibly knock their stamina down some first, especially if they go in fresh off a 10 min rest, or attack during said 10 min rest.

Keep the dead suns stat block's special attack damage instead of the updated damage in AA2.

Give it more resolve so it can phase through walls and use that special attack more often. Keep it mobile and retreat/attack again. Just use that attack on different targets when possible, I killed my group's blitz soldier with two good hits.

Maybe bump it's health up a little.

Or just throw two AA2 garragakals at them, the two less d6 is key.

[The Ragi]

Moving the fight into the ship is great, specially if he drops down next to the spellcasters.

Ignore the Morale instructions on page 36.

Give him extra Resolve points.

Turn the dissected bodies in the Starship Grotto into messy Void Zombies.

[BigNorseWolf]

Just burn people down instead of going for the guy with the electric gun.

[Nimor Starseeker]

Thank you all for Your Feedback : ) I hope and intend to bring my players characters to near death.