I'm having difficulty understanding what Parasitic Properties: This is an active load means in LTSpice given as an option in the current source configuration window. So I plotted out the schematics, one with the active load checked and the other without, and compared their simulated traces. Without being an "active load", the current source behaves just like how a current source should be - a constant 2A current through \$ I_1 \$ (top schematic and trace). But if I check the "active load", the current through \$ I_1 \$ stays constant at 2A only after voltage goes above 0.5V, and down to -16A when \$ V_1 \$ is -2V.

1. It makes no sense to me that the current source can sink 16A while I've already fixed it a DC value of \$ I_1 = \$ 2A - where is this extra 12A comes from?
2. I don't understand how a load can be modeled as a current source. Isn't a load a component or a sub-circuit that sinks current and dissipates energy? Current source supplies energy to the circuit - how could it supply electrons to the circuit yet dissipating more energy (that \$ 16A*2V=32W \$!) than the rest of circuit?) .

Perhaps a related question here: LTSpice active load current generator soft saturation