Injection from two strings to one string
brainfuck, 30 29 27 23 bytes

,[-[+.&gt;]-[&gt;+&lt;---]&gt;.-.,]


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Inputs are separated by a 0x01 byte.

This turns ["foo", "bar"] into fUToUToUTUTbUTaUTrUT. To recover the original two strings, take groups of 3 characters, find the one where the second letter isn't U, and split there.