What are the consequences of declaring a SQL Server Variable with two (or more) '@' symbols?

Ordinarily, I would declare a variable

declare @ConType int;

Or something akin to this.

Recently in a code review I encountered a decalration using a double '@' (like the built in @@rowcount, for example), i.e.

declare @@ConType int;

I notice that one can stupulate any (reasonable) number of '@':

declare @@@@ConType int;

And the variable should function ok. So, the following should work:

declare @@@@ConType int;
set @@@@ConType = 1;
select @@@@ConType;

Obvoiusly, the above is a little stupid, but my question is really whether there is any significance in declaring variables in this way? Are there any side-effects? Should we avoid doing so?