Olimar’s side special is the Pikmin throw where Olimar chucks the lead Pikmin is his party in front of him and depending on the type thrown different effects will occur.
This is the main method of attack in the Pikmin series
His Down Special blows the whistle which calls any wayward Pikmin back to Olimar’s side and also changes the next Pikmin Olimar will throw.
While this is certainly a move that makes sense for Olimar to have given it's usefulness in the main games I always felt Smash never really encourages you to keep Pikmin alive and thus this move sees less use than it should, but more on that later.
Also, it somewhat bugs me that Alph’s whistle pattern is the same as Olimar’s instead of matching its design from Pikmin 3.
While it’s hard to see in normal gameplay a small arrow is placed over the head of the Pikmin that Olimar will throw/use next. (Pay attention to the Yellow and Blue Pikmin)