Be there or be square

• When it is just me I have 3
• Yet when there are more, I have four
• My first two are double
• My last two can clarify
• Leave my middle one alone, though, and soon you'll be talking to yourself
• You'll know you have me when all of me points right back to you

What am I?

Hint:

Watch out! Snakes can be deadly

This time I'm sure, you're

a die

When it is just me I have 3
Yet when there are more, I have four

Die is pluralized as dice

My first two are double

The prefix di- means double indeed (e.g. dioxygen $$O_2$$)

My last two can clarify

ie is an abbreviation for id est which is Latin for "That is"

Leave my middle one alone, though, and soon you'll be talking to yourself

I, it's still me!

You'll know you have me when all of me points right back to you

The sum of all pips on a die is equal to 21, which correspond to the letter U in the alphabet. That can be interpreted as "you". (Thanks @Stiv !)

Hint

A famous dice combination in craps is Snake Eyes, which is the worst one you can get (pair of 1s), and that might have caused some people (fictional or real) to meet an unfortunate end.

• Always felt like I was so close to solving it, and now I think that's finally it! (if not I'll definitely leave my spot for someone else) Jun 21, 2022 at 14:48
• Yep, you got it! Ill reward you the answer when you're able to solve that last line. Ill give you a hint, if you choose to take it: rot13(tvira gung gurer ner znal inevngvbaf, gur ynfg yvar pna or fbyirq jura ersrerapvat gur gvgyr, juvpu pbhyq uryc gb pynevsl nyy bs gur qvr) Jun 21, 2022 at 15:04
• @kaitlynmm569 V qvq guvax vg jnf nobhg gur qvr orvat phor-funcrq, ohg V whfg pbhyqa'g svaq rabhtu whfgvsvpngvba sbe "zr" abg orvat gurer Jun 21, 2022 at 15:07
• rot13(Xabjvat vgf n phor vf gur svefg fgrc. Abj pbafvqre jung vg pbhyq zrna gb unir nyy bs gung phor-funcrq qvr) THE NEXT LINE MAY OR MAY NOT REVEAL MORE THAN YOU WANT rot13(Jura lbh hfr n qvr, jung nobhg vg vf pbzzbayl hfrq jvgu rnpu ebyy?) Jun 21, 2022 at 15:14
• The last line might be an obscure A1Z26-related way of saying that rot13(gur fhz bs nyy cvcf ba n qvr vf gjragl-bar - gur gjragl-svefg yrggre bs gur nycunorg vf 'H', juvpu fbhaqf yvxr 'lbh') - but I'm not 100% certain if that's the intention...
– Stiv
Jun 21, 2022 at 15:45

Are you perhaps

a bit

When it is just me I have 3

Bit has three letters.

Yet when there are more, I have four

Its plural is bits or can even be byte if there are eight.

My first two are double

The prefix bi- means "twice" or "two".

My last two can clarify

IT is Information Technology, the study of using computers for research, or send and transmit information.

Leave my middle one alone, though, and soon you'll be talking to yourself

I, that's me!

You'll know you have me when all of me points right back to you