Just curious on rules concerning climbing/clinging to/riding creatures bigger than you. Considering it's not really a grapple - you aren't immobilizing the creature, and a halfling would realistically never be able to grapple a dragon (CMB vs CMD would be nuts), but it's a different matter when you consider Bruenor on the dragon's back (Drizzt books), a monk clinging to the back of a giant or Legolas climbing the war elephant (well not quite that cheesy, but you get the idea).
They had a tactical feat for this in complete warrior. It was called giants bane. With this feat you had to move next to a creature 2 or more size categories larger than you and on the following round you made a DC 10 climb check to climb on to it's limbs or back. The creature could attack you at a -4 and to try to shake you off was grapple opposed by your climb check.
Just curious on rules concerning climbing/clinging to/riding creatures bigger than you. Considering it's not really a grapple - you aren't immobilizing the creature, and a halfling would realistically never be able to grapple a dragon (CMB vs CMD would be nuts), but it's a different matter when you consider Bruenor on the dragon's back (Drizzt books), a monk clinging to the back of a giant or Legolas climbing the war elephant (well not quite that cheesy, but you get the idea).
I'd consider it a climb check. Probably DC 20 if it had baggy-ish clothing you could hold onto, 25 if it was something large and smooth (like an elephant or dragon), and I'd raise it by 5 if it went into extreme motion (flight or a charge/run action)
What about relevant skill (climb, ride) vs CMD?