AIBU to find my friend's behaviour rude and increasingly irritating?

He is probably in the club of ND people that are all around us every day, probably including ourselves too.

How old is he?
sounds very immature behaviour

I get it now. I really feel
for you and wouldn’t wish to start diagnosing him. However he’s an absolutely weirdo and I’d not want to be alone with him if I were you. Very strange, very controlling and very rude

Omg he sounds like someone I went on a few dates with years ago
He took me to the theatre and he started shouting things out (Like you'd do at Rocky Horror but it was not Rocky Horror!). He did various other things like the motorbike noises. I wonder if it's the same man??
I presumed it was caused by extreme social anxiety/ND

It sounds to me as though he's eccentric - simple as that.

He doesn't sound especially performative, as this is behaviour he is exhibiting one-to-one - you haven't said he's all over social media doing 'I'm crazy, me!' posts about his exploits.

It's up to you whether you want to tolerate his behaviour - you shouldn't feel under any obligation to host him, your boundaries are yours to draw.

If he's generally a good friend, a kind, decent person who is there for you, personally I would tolerate some odd behaviour, but it's for you to judge whether the friendship is worth it.

Perhaps your friendship has just had its time?
He seems very strange, I’m assuming it wasn’t so apparent before…

Sounds like he could have an eating disorder or be on a diet

Yikes, very weird indeed.

Could it be some icky fetish he has going? Or is he particularly paranoid and wanted to be sure it wasn't poisoned?

Either way, very odd and I would feel quite uncomfortable with it!

None of the things on their own sound bad, weird maybe, though in long friendships, weird things can happen because they've been accepted so long. But it's the fact they're all happening and clearly he's changed, from what you said. He must be a good friend (to be the only one there on your birthday) so find out why he has changed. Ill? Stress? Using something?

Strange behaviour. I would of ate everything on my plate and when he asked half way through if I was done I’d say no

He's just getting on your tits isn't he ? Take a step back . Sounds like an attention seeking diva but that's not new is it ?

You could just say “no” when he asks for, or reaches for your plate, and tell him it makes you uncomfortable if he queries it. You could then suggest his own plate again.
The noises (and the above) sound like immaturity or he struggles to navigate social conventions.

I think I’d bring up the food thing before there’s a next time. Say to him ‘I want to be a good host, but you also have to be a good guest. If I invite you for dinner and you accept, don’t be a bad guest.’

The noise thing, just say ‘why the sound effects, you big weirdo?!?’ and continue like nothing happened.

No i coukdnt cope with that. He sounds about 16 or very socially inept and/or on the ASD spectrum , yeah, i know...

Surely you must have noticed his weirdness before now?? This can’t be all-new?

When I was flat-sharing in London in my mid-twenties I had a friend from school over for dinner as she was living in London, too. She was so strange that evening that I never saw her again. She had always been slightly odd, but in an endearing way. Last I heard, she’d disappeared and was a missing person. Turned out that she was fine, she’d just dumped her parents without bothering to inform them.

In terms of how she was strange that evening, it’s difficult to describe and was 25 years ago. Just odd inflections, weird speech patterns, pressured speech. Now I recognise it as mental health issues, I guess they were, but I didn’t realise back then.

All this is to say, a friend who was once endearingly eccentric can cross the line into being mentally ill. And that’s hard to cope with as a friend. At least with a family member or spouse you can get them into treatment.

Yeah and do you know what - some of them choose not to fit in with the social rules we follow. He sounds like an incredibly selfish weirdo.

Has he always been like this ?? It all sounds a bit off mentally......if this is a sudden change ge in behavior then it might be worth asking his friends and any family if they've noticed any changes too.

I’d have given him my plate after a few bites/when he asked and then 2 mins later got myself another plate. And felt I won!

I would say "I'm only going to serve myself the amount that I'll eat, so there won't be anything left". I don't understand why there was so much left on your plate, haha.

He sounds like he has special needs tbh. Is this the case?

A woman i know does the noise thing. She has ASD(does your friend?), I think for her it is almost a form of echolilia? Singularly, if someone's 'phone makes a noise or a microwave pings etc she'll make a similar noise.
Regarding the food as a pp said, it can be quite a difficult position to be put in when asked the open question 'what do you want?'. Once he'd said he'd have the leftovers I'd have said 'okay I'm making X, will make you some too, is that okay?' I am sure if it was something he despised he'd speak up. Sounds like a misplaced attempt to be polite.

Has another friend told him off saying “I often give you a meal but you never reciprocate” or similar?

So he wants food but is determined that afterwards he will be able say “You didn’t give me a meal, I just had your leftovers”?

I have a family member with a communication disorder and that would be their logic. They always grab anything that’s on offer but aren’t capable/willing to reciprocate so sometime get tangled up when they are called out.