Gas Planets vs Rock Planets

[PlutonianEmpire]

A while ago, in the Help forum, I posted about a rogue gas planet overcoming Earth. My question is, what happens to the gas planet, with a 32,000 km radius, and similar in composition to Neptune, when and after it consumes the Earth, never mind that such an event is extremely unlikely?

[Hungry4info]

A planet with a similar composition to Neptune will be an ice giant (e.g. Neptune, Uranus, GJ 436 b, HAT-P-11 b), whose interiors are dominated by ice. Gas giants are planets whose interiors are dominated by gas.

If SL9 was anything to go by, if a gas giant planet gets hit by an Earth-like object, it's going to make one heck of a bang. Earth will probably sink in and merge with the core, adding just another Earth-mass of matter to a 100+ Earth-mass planet. In the long run, I would expect the gas giant to just be slightly more massive, probably the same size.

[Planet X]

I imagine such an impact would leave an impressive "bruise" on the gas giant's cloudtops as well. Think of the Shoemaker-Levy impact magnified a million times! Later!

J P