If Prince Malchezaar in the hand is buffed, your opponent can see it on the side-bar

[Patashu]

• https://www.reddit.com/r/hearthstone/comments/5ijwac/strange_bug_with_malchezaargrimestreet_outfitter/
• https://www.reddit.com/r/hearthstone/comments/5jrx67/if_grimestreet_smuggler_buffs_a_prince_malchezaar/
• https://www.reddit.com/r/hearthstone/comments/5sorqt/interesting_prince_malchezaar_handbuff_interaction/

[Patashu]

Confirmed in 7.1

https://www.reddit.com/r/hearthstone/comments/5x5k2u/til_hand_buffs_reveal_prince_malchezaar_if_he_is/

[troggnostupidhs]

Confirmed 8.0

https://www.reddit.com/r/hearthstone/comments/64fxam/bug_prince_malchezaar_is_revealed_in_the_history/

[troggnostupidhs]

Confirmed 9.0

https://www.reddit.com/r/hearthstone/comments/6tudve/bugwhen_prince_malchezaar_is_buffed_while_in_hand/