Pick-a-Dog (first published as Formissimo) features the same gameplay as Pick-a-Pig, with the only difference being that dog noses in one game are replaced with piggie snouts in the other. An individual game supports 2-5 players, while combined they support up to eight players.
To set up the game, lay out 30 cards in a grid (49 cards with 6-8 players) and give one card face down to each player. Each card has five attributes, with each attribute having two states: large/small, light/dark, one/two arms, with/without sunglasses, and with/without popcorn. (As noted above, combining the two games adds a sixth attribute: pig/dog nose.) Someone shouts "Go!", then everyone looks at their card in hand. Players then start grabbing cards from the grid and stacking them in hand. The card grabbed must be identical to the top card in hand or differ from that top card in only one way. Thus, as you grab cards, the attributes of that top card will keep changing, forcing you to look for matches in new ways.
Once a player thinks he can't grab any more cards, he yells "Stop!". The round ends, and all players check their card stacks. If someone made a mistake when grabbing cards, that player keeps none of the cards gathered that round. If the player who stopped the round made no mistakes, he earns an extra card (two cards when playing with 6-8). If, however, he stopped the round when he could have collected more cards, then he loses all the cards he's collected during this round.
Whoever has collected the most cards when the game ends wins!