It's a console devcommand, just like spawn.

forcedelete 5 glowingmushroom

The 5 is distance radius in meters to apply the command (minimum 5, maximum 50). The glowingmushroom at the end is important to limit the forcedelete command to only that specific type of object.

5 meters is also the default, but you still have to specify it if using the command for a specific object type, otherwise it gets confused.