Do familiars disappear?

Appearing in an unoccupied space within range, the familiar has the Statistics of the chosen form, though it is a Celestial, fey, or fiend (your choice) instead of a beast. When the familiar drops to 0 Hit Points, it disappears, leaving behind no physical form. It reappears after you cast this spell again.

Can you concentrate on spells while Polymorphed?

interestingly the spell itself does not state that you can continue to concentrate on a spell while polymorphed, which could lead to something like a rat no longer having the mental ability to concentrate on the spell.

What happens to a familiar when it dies?

The 5e PHB is pretty unambiguous about familiar “death”. Per the find familiar spell description: When the familiar drops to 0 hit points, it disappears, leaving behind no physical form. It reappears after you cast this spell again.

Does a familiar disappear if the caster dies?

It remains in existence, for however long it manages to stay alive.

Do you lose concentration when Polymorphed?

Being polymorphed does not break concentration.

Can you talk while Polymorphed?

It retains its alignment and personality. The creature is limited in the actions it can perform by the nature of its new form, and it can’t speak, cast spells, or take any other action that requires hands or speech, unless its new form is capable of such actions.

Can you have a pixie as a familiar?

The find familiar spell lists the forms that the familiar can assume. Pixie and imp aren’t on that list. A warlock with Pact of the Chain gets a longer list. Yes, that variant is one way a DM can handle familiars.

Can a Tarrasque be killed?

Actually, the Tarasque is an imaginary creature in a game, so you can’t actually kill it since it’s not real. Joking aside, in DnD 3.0 you had to reduce it to -30 and use a Wish spell to kill it permanently, otherwise it inevitably regenerated.