D&D 5E Misty Stepping on my Dragon (critique my ruling)

[Scorpio616]

I'd say it was a bad ruling that let an over optimized and over-focused PC outshine the others.

 

[Ovinomancer]

Dragon Shaking off PC The dragon could use its ACTION to attempt to shake off PC with contested Ability Rolls of STR vs PC's STR(athletics) or DEX (acrobatics). Failure would result in PC potentially falling. I would grant a DEX save to avoid falling, probably in the 16-19 range. If PC succeeded he would be PRONE for the beginning of his next round. My question here, is that dragons are really tough in 5e. Should that contested ability check replace his whole Multi Attack for that round or replace one of its three attacks from its Multiattack? (Bite and two Claw)

Everyone has been great and has given me a lot to think about. Look forward to your replies.

On this, I would not allow a save to stay on after the dragon has used his action to successful dislodge the character. Recall that the rule on 271 grants advantage so long as the character is 'on' the creature, so prone would just result in regular attacks, not disadvantaged attacks. Allowing a character to fall prone on the creature without being dislodge only removes a benefit for the character; it imposes no disadvantage. I would not allow a second chance to remain on the creature once the creature successfully dislodges.

Further, I would keep the dislodge attempt as an action and not allow the substitution for another attack as part of multiattack. If a creature takes the effort to toss someone off, and the potential result of that would be falling a great distance if the creature is airborne, then that seems a good action trade off. Allowing a substitution results in the creature getting multiple attempts to dislodge the character, and that, ultimately, is biased against the players because they, over the course of the game, will have to defend against dislodging that much more often. It also reduces the effectiveness of the tactic against large creatures, which seems counterintuitive.