There are quite a bit of other mushrooms with red caps.

You don't ID by color. You ID by all the features of a mushroom: color, texture, cap shape, stem type, spore print, etc. Everything needs to match.

Panthers have dots on the top. The cap it often brown, but sometimes its bleached by the sun and nearly white or yellow, but still a panther. You can tell because of the stem type. No mushroom has dots on top, is the size of the panther, and has the same type of stem.

For example, look at this:



This is NOT the panther. How do I know? Some panthers are this color, and they don't all have dots on top. I know this is not the panther because the stem is not a panther stem. This is Amanita crenulata.

Look here:



No, it’s not A. muscaria. It’s A. parcivolvata. Muscaria isn’t the only red capped mushroom with dots on it!

Another red capped mushroom that isn't muscaria. It almost looks like it has a few white dots on the top, but doesn't really. They are just imperfect areas on the cap.



What about this:



Is this one A. muscaria? No, it's not A. muscaria. Anyone know what it is? I know. Try to guess.

Season and location are two very important determinant factors missed from your list. I am pretty good about mushrooms. I know many of the shrooms in the woods and fields round where I live. I totally know all about the shrooms of interest both magical and edible. I am the only living person that I know, who has found and eaten Wakefield Caps.

I never considered Spocksbrain not being in the UK.

Is that another parcivolvata, Ron?

I'm only familiar with American look-alikes, but parcivolvata is the only one with that striking red color and white dots, and the shape of the young cap and color of the stipe jibe with that identification.

You need to familiarize yourself with the identifying characteristics of A muscaria and A pantherina. The stipe, and especially the base of the stipe on Spock's mushroom don't look anything like the base and stipe of muscarias or panthers. This should have jumped out at you.

And never eat an Amanita if you're not 110% sure of your ID. This can be very dangerous, as burnt and polytrip pointed out.

Did the mushrooms that you ate really look exactly like this? With no rolled volval collar or concentric rings on the base, and a high (or absent) annulus?

Yes. You are right. That was another A. parcivolvata.

I put that up because I wanted people to think a little more about mushroom picking. Even the famous Amanita muscaria which some claim has no look a likes, actually does, which could fool some inexperienced mushroom hunters. If you went out looking for a red cap with dots, there are quite a few different kinds of mushrooms that match those ID features. You need to look at the entire feature set, not just the cap, or color, or size. All the details need to be looked at. But once you get the hang of it, it is easy, at least for me, it is. For me none of these mushrooms look at all the same. For me, no mushrooms look like A. muscaria or A. pantherina. They are unique and easy to identify by their entire feature set.

If a mushroom kind of looks like muscaria but you are not sure, DO NOT EAT IT. You need to be 100% sure of its identification before eating it.

The same holds true for fruit. Some berries can kill you if you eat as little as two or three.