How do I dodge the second boss's attack?

The second boss

has an attack in which it spits out blobs at you. I don't know how to dodge this attack.

I've tried flying over it by pressing up, ramming into it by holding the action button, hitting the panel that spawns in front of it, and just running into it without pressing anything. No matter what, I take damage. How do I deal with this?

Here is a screenshot of what I'm having trouble with (boss spoilers, of course):

This obstacle is equivalent to the spike obstacle introduced at the beginning of Level 2. Like the spikes, you can dodge it by flying over it.

As always, you can fly by holding UP while you thump a thump, and continuing to hold THUMP after thumping it. There should be a thump immediately before this obstacle which allows you to fly over it.