Tentacles come from the fights with the starting pirate girls. Get the COMBO meter to 50 and 100 to get guaranteed drops. The rarity of the tentacles is a tiny issue though so it might take a few fights.
Thanks, I saw in the guide that it is listed as dropping from them, so I figured. I think the issue is I usually beat them at around 45 combo meter, didn't realize drop rate was linked. Tyvm!
