Anyway, I want the player to be able to craft and place them him/herself, so I'm using an ordinary landmine, which when placed on the ground, I want to be replaced with the Spider Mine creature, which would then scamper off and do its thing.
The thing is, I'm not really sure how I'd go about scripting this. I figure it'd be as easy as disabling the mine and using a placeatme/moveto command to replace it with the robot, but I'm not sure which blocktype to use. I don't think "begin gamemode" would work, but what about "onhit"? Would that be right?