What is "terror of Bengal"?

Explanation:

The water hyacinth Eichhornia crassipes is regarded as the "terror of Bengal" because it thrives in ponds and outcompetes native flora, resulting in their extinction.

They also lower dissolved oxygen levels in the water and raise biochemical oxygen demand (BOD), causing aquatic animals to perish (such as fish). The "terror of Bengal" was given to this invasive plant since it was responsible for the death of so many plants.

Final Answer:

Water hyacinth.