This question already has an answer here:
A Kraken is able to grapple up to 10 creatures with its tentacles, the reach for this attack is 30 ft.
Tentacle. Melee Weapon Attack: +17 to hit, reach 30 ft., one target. Hit: 20 (3d6 + 10) bludgeoning damage, and the target is grappled (escape DC 18). Until this grapple ends, the target is restrained. The kraken has ten tentacles, each of which can grapple one target.
Can a creature with a reach of 5 ft. which is grappled 30 ft. away from the Krakens position attack it with a melee weapon attack? It would make sense, that one could aim for the grappling tentacle, but is it RAW/RAI?