The wiki of Carlos Rodrigo

The Cobra Effect

When a measure becomes a target, it ceases to be a good measure.
The Cobra Effect is the perfect example of incentives that back fire.
There’s a famous story of British colonialists trying to reduce the snake population in India.
They offered bounties for dead cobras with cash given out to the killers.
The incentives back-fired…
The local population started breeding cobras & killing them.
When the government discovered this, the reward programme was scrapped.
The cobra breeders then released their $0 snakes into the street, making the problem much worse.