Most MK's don't approach with nado anymore, afaik.Oh the spring? Well, it's only useful for distruption and edgeguarding (Spring says F your recovery Ike >:D).
Also useful for Tornado distruption, we can drop the Spring in there as you know. If MK Tornado's on to a grounded spring, it turns into a Side B for some reason ... Take advantage of this if you predict a Tornado, works wonders if used right.
The reason they'd go into side-B is because they're physically committed to tapping B while holding a direction. More cautious/aware MK's can either restart the tornado upon hitting the spring, or even dj d-air :[
Same thing for Olimar. He can just DJ on hitting the spring or either N-air or buffer a jab/tilt out of airdodge.
Also keep in mind that he can smash as soon as he plucks, so don't get caught off guard just because he doesn't have any pikmin. If he's on the ground, Almost always treat him like he has pikmin. :x
However, it's still an interesting diversion as long as you don't set it up late enough for them to be able to hit you out of D-air while they're respawning.
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On a related note to spring usage, has anyone tried a spring cancelled ledgehop aerial?
that is:
1) set up a grounded spring near ledge
2) D-air or fall into the ledge
3) FF>double jump a F-air/U-air/move of choice while aiming to land on the spring to cancel your aerial into either a D-air stall, HA, double jump, or just follow the spring's trajectory.