That would be Wilson, of course.
The event in question unfolded just as the humans were expecting company. Wilson's timing was exquisite. Herself came bustling out to the barn, wheeled in the refuse transporter and threw a large mass of "compost" into it. She regarded us distractedly, said "Ohhhh, flymasks" and disappeared into the barn. Wilson examined the large mass and without pausing for breath, scarfed the lot. The Woman returned, flymasks in hand. She looked highly puzzled and searched the area. Then she looked highly alarmed and, clutching the veterinarian's card, rushed off to make telephonic communication with him.
Wilson ate: a large coffee filter and grounds, bunches of green onions and a quantity of cabbage, amongst other revolting and slimy things. The Woman feared the filter would create some sort of clog in Wilson's digestive workings, causing him extreme distress as well as "weirdin' out the guests" as Wilson put it. I must note here that he developed the worst halitosis I've ever encountered and it endured unabated for the balance of the day.
The veterinarian's diagnosis: a large bran mash was prescribed, and a warning that though Wilson would probably be fine (it seems the filter is a form of fibre) the rich mixture of composting refuse would undoubtedly leave him highly flatulent and rather hyperactive for the near future. He was absolutely right. Wilson trotted around busily, enveloped in a cloud of vile green gas for several hours. The guests seemed quite impressed (or possibly horrified).
Next morning, Wilson was quite recovered. In fact, on his way out the door, he picked up a curry comb, brushed the floor with it, and then stepped across the aisle and began brushing my face. The Woman was highly amused. I was not.
Footnote: I should add that the veterinarian said horses often enjoy eating paper products and in fact one of his clients ate his own export papers, which had been attached to his stall door. Our dear, departed pony Daisy ate the larger part of a questionable publication called "Awake" or "Watchtower" or some such thing, left by a group of religious zealots. She absorbed none of the contents and remained a life-long heathen.