Thinking of Eidolon of lv5 Summoner with below settings:
Items: Amulet of Mighty Fists +2, Belt of Giant Strength +2
Feats: Power Attack(-2, +4), Improved Natural Attack
Evolution pool: 12 points (Half-Elf Wild Caller), Extra Evolution * 2 (lv1, lv5)
Evolution (Quadruped): Limbs(Arm)*3, Slam*3, Pounce, Improved Damage(Slam)
So a battle would start with a charge and followed by a full-round attack:
Bite: +10, 1d6+10
Slam * 3: +10, 3d6+10
Average damage is 13.5 + 61.5 = 75
A quick look at monsters shows most monsters of cr5 would be one-turn killed.
Just thinking how much damage a fighter could produce each round in level 5? Mostly 20 or even less.
So is there any rule I am missing? or should add some house rule to limit the Eidolon with multiple slam attacks?