Depression I might need to euthanize one of my pets

[GripMaxxing]

It’s old and sick, barely eats and is thin. Help me choose a way to kill it

 

[GripMaxxing]

I don’t wanna scare the poor thing in its final moments, so I need sedative drugs before I kill it

 

[GripMaxxing]

Fuck it I’ll just make a CO2 gas chamber

 

[Hobbit]

That's gross as fuck. Put it down humanely at a veterinarian clinic then get it cremated and keep the ashes (or scatter them in its favourite spot outside). Stay with it in its final moments at the vet clinic.
Don't do it yourself because you can fuck it up and inflict pain.