Ryan Reynolds is dead(pool) serious about these trick-or-treating rules.

The Proposal star issued a warning—a red notice, if you will—to his and Blake Lively's four kids that he won't stand for their Halloween costumes going against SAG-AFTRA's guidelines on what outfits actors should wear amid the ongoing Hollywood strike.

Variety reported that the union released instructions for its members to "celebrate Halloween this year while also staying in solidarity" with the protests, suggesting they "dress up as characters from non-struck content, like an animated TV show" instead of recent blockbuster films like Barbie.

In response to the outlet, Ryan, 46, joked that he'll be honoring their proposal by calling out his 8-year-old daughter James for crossing picket lines.

"I look forward to screaming 'scab' at my 8 year old all night," Ryan tweeted. "She's not in the union but she needs to learn."

In addition to keeping their eldest in line, the couple—who also share Inez, 6, Betty, 4, and a baby whose name and sex have not been revealed—are supporting the strike by funding actors out of work.

In August, Blake and Ryan donated $1 million to the SAG-AFTRA Foundation, which provides emergency financial assistance to performers on strike. (Other couples to each give the eye-popping sum were George and Amal Clooney; Luciana and Matt Damon; Hugh Jackman and Deborra-lee Furness; and Jennifer Lopez and Ben Affleck.)

Although Blake and Ryan are backing up other actors in their industry, they aren't too thrilled with the idea of their kids following in their footsteps into acting.

As Ryan quipped on Today in 2015, "I worry that my daughter's going to want to go into show business!"

"You worry about really stupid stuff," he added. "And you sorta sit there and go, 'Oh gosh, is she gonna wanna do this?' I like to whisper in her ear, like, really normal everyday jobs... 'You're going to be a flight attendant...a barista...Just normal, wonderful jobs that you can have a nice, normal life.'"

As the actor prepares to help James, Inez and Betty pick out their normal Halloween costumes, see more stars celebrating spooky season this year:

The Last of Us star avoids zombies during a visit to Universal's Halloween Horror Nights.

It's knives out for the star's Halloween Horror Nights trip.

The Vanderpump Rules star and What We Do in the Shadows actor are scared stiff during their Universal Studios outing.

The Oscar winner holds his own amongst a crowd of creepy clowns.

The father-daughter duo rock out at Halloween Horror Night in Hollywood.

The couple enjoys a frightening date night at Universal Studios Hollywood.

The JoBros' youngest sibling has a scary good time at Halloween Horror Nights.

THe star and her son Sebastian get spooked at Halloween Horror Nights at Universal Studios Hollywood.

The Bel-Air star is scared silly at Halloween Horror Nights at Universal Studios Hollywood.

Despite being surrounded by some creepy characters, the singer is all smiles during a visit to Halloween Horror Nights at Universal Studios Hollywood.

The singer has a blast at Universal Studios' Halloween Horror Nights.

No laugh here! The Saturday Night Live mainstay tries to survive Universal Studios' Halloween Horror Nights.

(E!, Universal Studios and Today are both part of the NBCUniversal family.)