Pressing B while underwater makes Mario grab however you can only grab Koopa Shells that are occasionally hidden in the clams.
you press jump then press L note:this answer is only for super mario 64 ds
Assuming the game in question is Super Paper Mario, press A.
for the super Mario bros wii press the A button to swim
In Super Mario 64, press B. In Super Mario 64 DS, press your attack button. (A with the default settings) In New Super Mario Bros., walk into it while holding your dash button. In Super Mario Galaxy, you can't pick them up.
press z on the mark of 2 and press A at go
You shrink to super Mario automatically and die
in all Mario games except super Mario 64 ds you press the (a) button
Press Spacebar twice.
press c
Press B
press a behind him 3 times. he will give you a star. this is in super Mario 64
Press P then press exit then press quit game or exit level