Christ under the appearance of stone!

Many Protestants who object to calling Peter the rock in Matthew 16:18 will appeal to a completely unrelated mention of Christ as the rock in 1 Corinthians 10:4

and all drank the same spiritual drink. For they drank from the spiritual Rock that followed them, and the Rock was Christ.--1 Corinthians 10:4 

Now, obviously this is not talking about a rock used for building, but rather the rock mentioned in the Torah that the Israelites drank from after Moses struck it

Then Moses raised his arm and struck the rock twice with his staff. Water gushed out, and the community and their livestock drank.--Numbers 20:11

Behold, I will stand before you there on the rock at Horeb, and you shall strike the rock, and water shall come out of it, and the people will drink.” And Moses did so, in the sight of the elders of Israel.--Exodus 17:6

Now, I have not met many Protestants that object to the rock being Christ since it says "the rock was Christ."  Some ignorant of the context initially deny it since they only are familiar with the verse when debating Matthew 16:18. However, what does this mean? Christ appeared to God's people in the Old Testament "under the appearance of stone" from which they drank (on more than one occasion), as St Paul calls the water that it produced "spiritual drink." This is important to note since St Paul speak later in the chapter and in the next chapter (11) about the Eucharist, in which those of us who profess the real presence believe Christ "under the appearance of bread and wine." After mentioning the stone in verse 4 St Paul states:

Nevertheless, with most of them God was not pleased, for they were overthrown in the wilderness.--1 Corinthians 10:5 

This brings to mind a verse later in St Paul's discourse on the Eucharist in chapter 11.

Whoever, therefore, eats the bread or drinks the cup of the Lord in an unworthy manner will be guilty concerning the body and blood of the Lord.  Let a person examine himself, then, and so eat of the bread and drink of the cup. For anyone who eats and drinks without discerning the body eats and drinks judgment on himself. That is why many of you are weak and ill, and some have died.--1 Corinthians 11:27-30