If someone says they went to Burger King and "got a suicide," it is not a cause for panic, nor are they making a quip about how unhealthy the food is.
They are instead referring to a mixture of at least two but usually three or more sodas. Legend has it, all suicides taste the same.
Not typically used to refer to alcoholic drinks, which may lead to actual suicide (if accidental). To avoid confusion, "suicide drink" can also be used.
I got a suicide (drink) at Burger King with Coke, Mountain Dew, Dr. Pepper and Sprite. Tastes exactly like every other suicide I've ever made.