Creating a Mario-style Butt Stomp Move

I'm trying to implement a ground pound/butt stomp move that allows the player to effectively slam into the ground regardless of what height they've jumped up to or if they are are already falling from a jump. Here's an example from one of the New Super Mario Bros. Games: -

I've tried a couple of different solutions where if the player is jumping or falling and hits the down key, gravity is temporarily increased but this doesn't really work as intended (possibly because the slightly pause is needed when the move is triggered to heighten the impact). I feel like there might be a better solution; does anyone have any ideas? I'm currently using the platform behaviour with double-jump enabled if that makes any difference!

Thanks!

Probably give them the bullet behaviour and set the angle of motion to 90 and speed according to the speed of the slam. Obviously enable/disable the behaviour itself during this move. I made a boss that slams down by using this, you have more control over the slam than just for example if you were letting the platform behaviour 'fall' and relying on the gravity.

Perfect, managed to get this working as intended! You're right, using bullet has actually opened up some other possibilities alongside the extra control. I haven't quite worked out how to do the pause at the height of the attack yet; I guess I could look at the player's X and Y values when the down key is hit, disable gravity temporarily, hold the position for a moment, and then reset it when the player hits an enemy/ground?

Yeah reducing the gravity and I think setting vector values to 0 can stick them in mid air as well.