So you only want the printed text on the card; the first hunch is to access the copyable abilities of the card.
It's sort of hacky, but what about "All other Slivers gain all copyable abilities of enchanted creature."
I get it. (In fact I got it about an hour after I posted but you have confirmed the depths of my lack of knowledge, I thank you all)
Ok, bring this down to my level of game understanding and below (not much further to go then, eh?) How do you define what's copyable? Are only keywords copyable?
If so, the problem with slivers is that none have keywords. They all just have abilities that
grant keywords & abilities.
What about having:
All Slivers gain "T: This creature loses
all other abilities and becomes an Aura enchantment with enchant creature. Attach it to target creature. You may pay 0 to end this effect.
Enchanted creature is a Sliver. All other Slivers gain the
printed abilities of enchanted creature"
They used this wording in Vs for some effects and it works pretty well. This way your Tim & Muscle Sliver look like this:
Tim
T: Ping
Tim is a Sliver.
Tim has +1/+1
All other Slivers gain "Ping". (don't know if this would appear given that it's specified on the Aura)
With an enchant creature Aura attached that says:
"Enchanted creature is a Sliver. All other Slivers gain the printed abilities of enchanted creature.
You may pay 0 to end this effect."
Your Muscle sliver is:
All Slivers have +1/+1
T: Ping
I have a question (and I'm presuming in my example above that the answer is no): Is the Aura is still considered a Sliver or not?
The fact of it becoming an aura should mean it's no longer a sliver, if it also loses all other abilities then other Slivers don't gain the "T: This creature loses all other abilities...." etc ability.
The question really is, do you want other creatures to have the "become an Aura" ability if the Licid Sliver is already an aura?