Can someone help me fix this error?

[lilac flax]

you have to add_child()

[thick vector]

but it's the part of an enemy

I have a reference to it

[pulsar perch]

can we see the line that it's referring to with context?

[thick vector]

The error is refering to this higlighted line of code to where if player exits the zone it starts the timer

[old lance]

where did you define beahvior_timer?