Kids who have their faces decorated with blue paint have been banned from a zoo enclosure - because they're freaking out the monkeys!
Twycross Zoo's face painter now has to warn kids who want blue designs that they won't be allowed in.
It comes after zoo staff discovered what was troubling three marmosets, who started panicking in front of visitors.
They worked out that the monkeys only did this when kids with blue face paint were around.
A zoo spokeswoman said experts could not explain why blue face paint was particularly scary.
"Whatever it is all three marmosets did not like it. They were running up and down the branches," she said.
"First of all they act all brave and try to warn people off, but then they run away.
"All the other children with their faces painted have not caused any problems."
The monkeys live in the South American tropical house at the attraction in Warwickshire.