diff --git a/bash/sponge b/bash/sponge
new file mode 100755
index 0000000..615853a
--- /dev/null
+++ b/bash/sponge
@@ -0,0 +1,18 @@
+#!/bin/bash
+
+echo -e "\nspongifying $@...\n\n"
+
+str="$@"
+lstr="${str,,}"
+ustr="${str^^}"
+
+# https://stackoverflow.com/a/10552175
+for (( c=0; c<${#str}; c++ )); do
+ # https://stackoverflow.com/a/1195035
+ if [[ $((1 + $RANDOM % 10)) < 5 ]]; then
+  echo -n "${lstr:$c:1}"
+ else
+  echo -n "${ustr:$c:1}"
+ fi
+done
+echo; echo