Flipendo, of course
Hogwarts Legacy adds more and more combat challenges as you pick up more spells, and at some point, it kind of hits critical mass. One such challenge is “flip a Troll’s club,” which is incredibly vague. Here’s how to do it, and how to complete the similarly cryptic “hit a Troll with its own boulder” challenge.
How to flip a Troll’s club
To flip a Troll’s club, you’ll need to use the quite literal Flipendo spell. You’ll acquire Flipendo through Professor Garlick’s second assignment: after you complete the initial tutorial for the herbology class in the main story. There are, however, timing considerations.
To actually get the club to flip into the Troll’s face, you’ll need to wait until it slams its club on the ground. Dodge (instead of using Protego), and cast Flipendo when the club is on the ground. It’ll “flip” back up and smack the Troll in its face. Challenge completed!
After you’ve acquainted yourself with the timing, it’s a useful way to take down Trolls quicker.
How to hit a Troll with its own boulder
The other Troll-centric challenge doesn’t need a spell at all. Instead, you’re going to be throwing a boulder (an object the Troll creates itself) with the right shoulder button when the timing is right. Run far away from the Troll to coax out its boulder attack. Then when it raises the boulder (which the game will telegraph as a Protego block), you’ll need to throw it back at them like you would any barrel or crate.
To ensure that you have time to actually pick the boulder up before it hits the ground and becomes non-interactable, just tap the Triangle (Y on Xbox) button to cast a short Protego block.