We know little kids that's scared can move from one place to another, kind of fix whatever bothers them, such as how Harry's hair grew out once cut. How do you imagine an upset baby would make magic manifest?

 

'Isobel later told her daughter that she had displayed small, but unmistakable, signs of magic from her earliest hours. Toys that had been left on upper shelves were found in her cot. The family cat appeared to do her bidding before she could talk.' - Pottermore on McGonagall.

I imagine it'd be the same as accidental magic, just less directed.

 

I meant if the infant was upset. Angry, scared, started screaming and the results freaked out a Muggle. And when I say freaked out, I mean scare them, not cause a WTF moment. What kind of thing could have happened? I need a dramatic example.

 

All their dolls starting to move on their own, slowly climbing after the intruder. Sudden drop in temperature. Electrical things turning on and off by themselves.

Or you could go the Addams family route and have the kid belch fire at them.

 

The same way it does in muggles?

 

I assume it would be through the strange, inexplicable (to Muggles) events occurring around the infant. For example, perhaps hair might change colour, the infant would move around a room or building in a subconscious attempt to escape, or maybe the cause of distress would suddenly disappear or be shielded against (mentally, physically, or metaphorically).

 

The smell of sulfur around the child?

Pentagrams appear in the air?

Cats tear their faces of?

Walls start to bleed?

Water in the tap begins to boil?

A portal to Zuul's domain opens in the fridge?

 

These sound pretty dangerous to me. Even magical families would need to take some precautionary measures to ensure the infant's safety.
Can't imagine how they expect non-magical parents to deal with the same issue, although I think fires and explosions are not common manifestations of underage magic.

 

Yes, I assumed that, I was merely contemplating on the dangers of these examples.
Even if they are not likely to happen, one might need to expect something similar to occur when raising a magical child and take precautions accordingly.

 

In stories, there are claimed of baby bindings on magics. A wand focus and helps control magic, I wonder if there is an object to help manage magic use in infants. The only issue that hindering their magical development might be bad for the child.

 

Accidental magic doesn't have to be violent in nature. Lily could make flowers bloom and Harry shrank a sweater until it didn't fit him, while Neville bounced when he should have splatted. A lot of accidental magic, at least outside of wizarding families, may just be put down to coincidence. Like say a mysteriously refilling bottle of milk or music boxes turning on by themselves.

 

I am imagining toys that act as magical lightning rods, attracting and collecting wild magic. They could create lights and sounds to entertain and sooth a child.

 

The issue to consider in my opinion is the magnitude and frequency of these these incidents of underage magic. If eruption of fires and explosions were the norm than you are in for a panic attack every time a baby starts crying or a child throws a tantrum. In the same way if they are frequent enough they can be a massive risk to the statue of secrecy in case of muggleborns.

 

Summoning toys and bottles. Magically amplifying their cries if no one responds to them. Removing or tearing clothing of their mother if they want to nurse (breastfeed). Turning on music. Simple things that muggle infants desire, a magical infant could make manifest.

 

Well, think of the examples in the book that were given. Harry was able to regrow his hair (which if I'm right has caused a lot of fics to be written with him being a Metamorphmagus), Neville was able to bounce after his Great Uncle Algie threw him out of a window, Voldemort using magic for some darker things when he was young and I think that's really about it. So I don't see it being out of the realm of possibilities that magic would manifest in any way possible and can fall between all those spectrums or into none of them at all.

 

I feel like magical infants would be able to conjure whatever they desire, like toys or food.