To all of us, to his friends, to the bullies who thought of the nickname, to everyone besides our parents and his teachers, he will always be Twitch. Whenever we’re at some stuffy family function, and I’m forced to call my brother by his real name, it always feels fake, like I’m talking about some stranger.

“It was the first thing I knew about him,” Dad would always say, his attempt to normalize his son’s behavior, as if it needed to be normalized. “When I held him in the delivery room his little bald head twitched in the palm of my hand, his eyes wouldn’t stop blinking, and I thought, well isn’t that interesting.”

It’s not continuous, it’s not every five minutes, it’s not every hour. Hell, it’s not even every day. But it does happen on a somewhat regular basis. Our parents, his pediatrician, all cavalierly diagnosed it as Tourette’s Syndrome and never thought twice about it. Because, what else could it be?

He took the name in stride, never considering “Twitch” an insult. “It doesn’t bother me,” he once told me, “Because I’m not twitching, Sam. I’m wincing.”

“Like, wincing in pain?” I asked inarticulately, surprised he was openly talking about it, especially to me of all people, his pissant little brother.

“Not pain. Fear.”

Years later, after starting our own families and when the twitches became more frequent, he finally told me everything in a confessional tidal wave helped along by whiskey and time. But by then I had figured it out, pieced it all together. “It was the zoo, wasn’t it?” he asked as a blanket of relief sobered him up, staring at something unseen in the setting sun.

“Yeah Twitch, it was the zoo.”

The Los Angeles Zoo is nestled in the hills of the city, hidden within a web of freeways and hiking paths. Whenever someone visited from out of town, they were shocked to learn such a compact zoo was wedged in the hills behind where they filmed ER and Friends. Like any zoo, there were always empty enclosures either under repair or in transition, waiting for a new animal to arrive from a far-off land.

One summer day, I ran towards the wide-open giraffe enclosure, seeing that they were eating the leaves off the trees above the viewing area. But Twitch had stopped behind me, leaning against the rail of an empty enclosure.

I made my way back to him and asked what he was doing. Between erratic twitches, never taking his eyes off the empty enclosure, he whispered, “I just don’t understand why I’m the only one who sees them.”

“Sees what?” I asked.

“Ah, nothing. Let’s go check out those giraffes.”

Later, we passed another closed enclosure sharing a fifteen-foot wall with the Bengal tiger next door. The big cat was sleeping unseen in its man-made cave high on its hill. As I waited on my tippy toes, hoping it would wake and show itself, I again noticed Twitch staring into the empty enclosure we had just passed.

“Seriously, what are you looking at?”

“They find refuge in the empty ones,” he said as his eyes blinked like they were sending me a message in morse code. “I like the zoo because the ones I see here seem peaceful, like they’re hiding from the others.”

Before I could ask him what exactly he meant, a guttural scream cut through us both. We turned and saw a mother screaming in front of the neighboring tiger exhibit. Her toddler had toppled over in a failed attempt at an ill-advised photo, landing in the tall grass amongst the unseen tiger.

I saw the tiger’s ears first, popping up from deep within its cave. Sensing something new. Something fresh.

The screaming mother was looking frantically around for help while reassuring her child that everything was going to be okay. It wasn’t. I knew it. Twitch knew it. The mother knew it. She had seconds to act now that the tiger was at the edge of the top rock, looking down at his surprise lunch.

A zoo-decaled golf cart screeched to a stop behind the mother. She turned to the zookeeper and screamed and pointed towards the tiger enclosure in one wild action. A thud like a meteor hitting the earth pulled both Twitch and I back towards the toddler, assuming the noise was the tiger’s deathly pounce. But it was something else I couldn’t see.

But Twitch could.

Something he’d always seen.

Something landed in the grass between baby and Bengal, the grass pushed down by an invisible weight. The Tiger snarled and lunged and was bluntly stuck midair by the same invisible force. The sound of the tiger’s pained squeal drew both zookeeper and mother back to the enclosure just in time to see the toddler midair, tossed out of the enclosure then haphazardly caught by the two shocked adults.

They didn’t see the toddler get picked up from the grass by an invisible claw. They didn’t see it recoiled back like a kickball then tossed back to safety. The same thunderous thud shook the enclosure again and we followed the sound back into the empty exhibit next door, logs and wheat flattened by nothing. A plume of dirt burst into the air like an invisible something plopped to the ground in an exhaustive huff.

I spent the rest of the day staring into the empty enclosure, hoping I’d see what Twitch had always seen. “You said these seem peaceful. What are the others like?”

“Not,” he said between winces.