They look cute ,when they are sleeping.
Knock them out early morning (game time), they are very slow and won't wake up during taming process.In Ragnarok there is a mountain cave between lava biom and Viking bay. You can find them there .fly through sea area the cave will be easily spotted .
These bad boys/girls only spawn in the artifact of the cleaver cave on mobile. They’re relentless during the night time so only knockout during day time. Oviraptor eggs will be the most time consuming part of trying to tame a mega.