West Bengal just voted out Mamata Banerjee. And some of the biggest issues that drove the result was Bangladeshi illegal immigrants, a porous border, and a changing demographic. The BJP won by making one argument — that Mamata had let in too many people from across the 4,096-kilometre border that India cannot fully seal. And the BSF's solution? Crocodiles. Literally. An internal communication dated March 26 ordered personnel to explore deploying reptiles in riverine border gaps. But beneath this darkly absurd border policy lies a genuinely complex bilateral relationship. Bangladesh's new BNP government wants to reset ties — its foreign minister made New Delhi his first overseas destination. Bangladesh needs India's diesel via the Friendship Pipeline. India needs Bangladesh to keep China away from the Chicken's Neck. Neither country can afford to let the relationship collapse. And neither country has figured out how to fix it. This is the full story of India's most complicated neighbour.