The blocks do not raise in the hollow using stealth elf what else can ..

Switch to a difference skylander just long enough to get past the blocks then switch back. You can switch skylanders in the middle of a level any time you want. At least on the XBOX you can, I do it ALL the time. I switch to one that has a power I need, like a LOBBER to knock those shooters off their platforms, or a FIRE GUY like ERUPTION to get past the zombies in darklight crypt that are immune to everything except fire. When I get in the final BOSS fight at the end of a chapter and my guy is getting the warning sound, I jerk him off the portal and replace him with someone else. That way I get through the chapter with NO LIVES LOST.