D&Dtools

You cause a creature's multiple arms or tentacles to fuse together into a single pair of stronger limbs.
Only limbs that the creature can use as arms or grasping limbs are affected by the spell (so basilisks and monstrous centipedes, neither of which use their limbs to attack or manipulate objects, are unaffected).
For every set of limbs fused into the primary set of limbs, the creature gains +4 to Strength when using those fused limbs (affecting activities that would use those limbs, but not activities relying on its bite, legs, and so on).
For example, a girallon under the effect of this spell would have one pair of arms and Strength 30 for the purpose of using those arms.
A behir, which has three pairs of limbs that it can use as arms, would end up with one pair of arm-limbs with a +8
bonus to Strength for those arms (its six legs would be unaffected).
The loss of limbs reduces the number of attacks available to the subject.