First make sure that the mantis is free from other animals. Take care of the mantis. Hug with a dragon or another big animal that does not attack the mantis. And then you can calmly give him the deadworm horns
Please don’t listen to the boy who said with bug repellant, ghille and cactus broth that the aggro range is “literally zero” cause it’s not.. you can get super duper close without aggravating it but you can’t get too close so still be careful and try not to stand so close you can touch it or it will STILL AGGRO.