Yes, a cucco riding the ground.
After you get on the shell and go past the giant robot, you have to jump to that platform. I kept running into the far edge of the platform. My solution is to stop boosting after I land.
EDIT: Finished another attempt today... 2:23:51. Definitely my best so far. There were two deaths: one in the Cave of Bad Dreams cost about 25 seconds, and one in the Iron Mountains cost about 20 seconds. Taking other various errors into account, sub-2:23 is definitely possible. I don't anticipate being able to work on this run for quite a while, though, so I am debating whether to submit.
EDIT2: Decided not to submit. I will keep going until I get sub-2:23.
EDIT: Finished another attempt today... 2:23:51. Definitely my best so far. There were two deaths: one in the Cave of Bad Dreams cost about 25 seconds, and one in the Iron Mountains cost about 20 seconds. Taking other various errors into account, sub-2:23 is definitely possible. I don't anticipate being able to work on this run for quite a while, though, so I am debating whether to submit.
EDIT2: Decided not to submit. I will keep going until I get sub-2:23.