We call it oscillation rather than "spike". To see how it's brought up, inspect more circuit voltages and currents.
You see heavy oscillating flyback current, probably unrealistic high leakage inductance.
There are some hidden component parameters, e.g. output capacitor ESR. You apparently have some 10 mOhm ESR.
Besides too high gate driver voltage (would damage a real MOSFET), you have two circuit faults:
- ground connection of input voltage is shorting a rectifier
- DCR diode has insufficient voltage rating