I've seen this theory thrown around and I wonder if Oda will ever use it. We've seen Snakeman and Tankman being incorporated into Boundman I think.
This page incorporates both Snakeman and Tankman in Boundman.
Snakeman - "Keep going Python, Don't slow down"
Tankman - "Is it hard. Is it soft?" which is the same as "he's rubber in an armament state"
Will we see a more permanent fusion to beat Kaido?
This page incorporates both Snakeman and Tankman in Boundman.

Snakeman - "Keep going Python, Don't slow down"
Tankman - "Is it hard. Is it soft?" which is the same as "he's rubber in an armament state"
Will we see a more permanent fusion to beat Kaido?