The “Tentacle to GoPro Adapter” is for GoPro 3/4 wich are using a special 10 pin Mini USB 2.0 connector wich integrates analog audio inputs.
GoPro 5 has a completely different USB 3.0 Type C connector. Sadly this connector does not offer analog audio inputs anymore but digital audio inputs instead. GoPro offers a clunky Microphone Adapter for the GoPro 5 wich is in fact an AD Converter wich is powered by the GoPro.
So theoretically it should be possible to connect a Tentacle to a GoPro 5 via this audio adapter but one should ask himself if this does make sense.