Penrose diagram of a black hole with imaginary charge.
If charge is imaginary, then electromagnetic energy is negative. This is a totally imaginary situation that is even less likely to occur in reality than other weirdnesses in black holes.
The point of considering imaginary charge is that an infaller could pass through the singularity in this case, and how could Andrew resist the challenge of visualizing what it would be like to pass through the singularity of a black hole?
It's oof through the singularity, ouch through the inner horizon, back ungh through the inner horizon, and eergh through the singularity again. Four universes are visible from the white hole: our original universe, a parallel universe, an antiverse, and a parallel antiverse.
Penrose diagram of a charged black hole