Oh no, the deer ate your Opuntia
And I thought I was so clever. But this is actually very good to know, thank you.
I do know the tastes of deer vary wildly and I have noticed deer eating or at least tasting a few things that are supposedly poisonous to them, especially during winter and spring when they are starving. The question then is how much of a toxic plant that is actually fatal. Maybe they need to eat a large amount.