They're known to be a tight knit family.

So it's no surprise that Alyson Hannigan and her clan made Halloween a family affair.

The actress, her husband Alexis Denisof and their daughter Satyana and Keeva all dressed as frogs as they hit the streets of Los Angeles on Friday to go trick-or-treating.

Four frogs: Alyson Hannigan, Alexis Denisof and their daughters Satyana and Keeva trick-or-treated in Los Angeles on Friday

All four family members sported frog heads that looked to be made out of helmets with large eyes fastened to the top.

Metallic body suits in a range of hues simulated the look of tropical rainforest frogs.

While parents Alyson and Alexis had white bodies, Satyana, five, and Keeva, two, were mostly purple and blue.

Happy Halloween: Two-year-old Keeva lost her frog hat at one point but kept smiling

Ready for candy: Satyana looked ready to trick-or-treat like a pro in her costume

The outfits were completed with fake orange hands and feet to complete the amphibious look.

Other than the occasional helmet slip - Keeva lost her frog hat at one point - the costumes seemed to be a rousing success.

Alyson, 40, and Alexis, 48, have been married since 2003.

Family: Hannigan and Denisof met while co-starring on Buffy The Vampire Slayer and married in 2003

Lilypad: Alyson played Lily Aldrin - a big fan of Halloween - on How I Met Your Mother for 9 years

In addition to co-starring on one season of Buffy, both actors have appeared in guest roles on the other's shows.

Alyson reprised her role of Willow Rosenberg on several episodes of Denisof's spinoff, Angel, and Alexis recurred as news anchor Sandy Rivers on How I Met Your Mother.

The impetus behind these frog costumes is not known, although it should be known that Hannigan's character, Lily Aldrin, on How I Met Your Mother was often called Lilypad by her TV husband.

Enough: The tadpoles did look a little tired as the afternoon moved into evening