Can't solve warlock's apprentice puzzle

I looked at a solution but the minion that I can’t target with spells doesn’t have taunt. It has taunt in this video so in the video it can be attacked. So I can’t do this solution. The only taunt is the giant mastadon.

I can’t link so just search on Youtube:

Hearthstone Warlock’s Apprentice. NEW SOLUTION

They changed it back to its original stage
https://youtu.be/wpwZhJ1WCow?si=crqhV2TB6DFN-p5D&t=341