Brad Pitt and Zach Galifianakis Brad Pitt and Zach Galifianakis

This week, Jenny Slate and her husband Dean Fleischer-Camp released a new video in their "Marcel the Shell with Shoes On" series, and Brad Pitt was Zach Galifianakis' guest on "Between Two Ferns." Bill Murray offered parenting tips and a nun provided us with a killer cover version ofMadonna's "Like a Virgin." And Shia LaBeouf got the weirdest (yet oddly fitting) musical tribute ever. Check out those clips and more in our weekly roundup of the best online videos:

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Marcel the Shell with Shoes On, Three: Marcel is back! Everyone's favorite shoe-wearing shell spends a day having all kinds of adventures after he accidentally gets locked out of the house.

Dachshund's Creek: Presenting your weekly "Why didn't I think of that?" moment: Someone reimagined Dawson's Creek as "Dachshund's Creek." You know, with dachshunds. (Spoiler: The one playing Joey has more charisma than Katie Holmes.)

Jim Carrey's SNL promos: Saturday Night Live returns this week with host Jim Carrey. And judging from these promos, it's sure to be a spooky episode ...

Brad Pitt on "Between Two Ferns": Brad Pitt's appearance on "Between Two Ferns" may be even better than President Obama's. Sample question from Zach Galifianakis: "Is it hard for you to maintain a suntan? Because you live in your wife's shadow."

Bill Murray's Parenting Tips: Here, father of six Bill Murray offers parenting advice to new dad Jimmy Kimmel. Find out how to cure your newborn's gas and more:

Nun Sings "Like a Virgin": Move over, Ms. Aguilera — there's a new Cristina in town with the voice of an angel. Introducing Sister Cristina, a nun who won the Italian version of The Voice. Listen to her enthralling (and controversial) cover of Madonna's "Like a Virgin" here:

"Shia LaBeouf": This song by Rob Cantor "tells the true story of an actual cannibal."